detectImportOptions

Create import options based on file content

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Syntax

opts = detectImportOptions(filename)
opts = detectImportOptions(filename,Name,Value)

Description

example

opts = detectImportOptions(filename) locates a table in a file and returns its import options. You can modify the options object and use it with readtable to control how MATLAB® imports tabular data. The type of the options returned depends on the file extension. For example, the function returns a SpreadsheetImportOptions object if filename is a spreadsheet file. However, the function returns a DelimitedTextImportOptions or FixedWidthImportOptions object if filename is a text file.

example

opts = detectImportOptions(filename,Name,Value) locates a table in a file with the help of additional parameters specified by one or more Name,Value pair arguments.

Examples

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Open Live Script

Detect import options for a spreadsheet file, specify the variables to import, and then read the data.

Create an import options object from a file.

opts = detectImportOptions('patients.xls')
opts = 
  SpreadsheetImportOptions with properties:

   Sheet Properties:
                        Sheet: ''

   Replacement Properties:
                  MissingRule: 'fill'
              ImportErrorRule: 'fill'

   Variable Import Properties: Set types by name using setvartype
                VariableNames: {'LastName', 'Gender', 'Age' ... and 7 more}
                VariableTypes: {'char', 'char', 'double' ... and 7 more}
        SelectedVariableNames: {'LastName', 'Gender', 'Age' ... and 7 more}
              VariableOptions: Show all 10 VariableOptions 
	Access VariableOptions sub-properties using setvaropts/getvaropts
           VariableNamingRule: 'modify'

   Range Properties:
                    DataRange: 'A2' (Start Cell)
           VariableNamesRange: 'A1'
                RowNamesRange: ''
           VariableUnitsRange: ''
    VariableDescriptionsRange: '' 
	To display a preview of the table, use preview

Modify the options object to specify which variables to import.

opts.SelectedVariableNames = {'Systolic','Diastolic'};

Use readtable along with the options object to import the specified variables.

T = readtable('patients.xls',opts);
summary(T)
Variables:

    Systolic: 100x1 double

        Values:

            Min         109   
            Median      122   
            Max         138   

    Diastolic: 100x1 double

        Values:

            Min           68  
            Median      81.5  
            Max           99
Open Live Script

Create import options, tailor the data types for multiple variables, and then read the data.

Create an import options object from a text file.

opts = detectImportOptions('airlinesmall.csv')
opts = 
  DelimitedTextImportOptions with properties:

   Format Properties:
                    Delimiter: {','}
                   Whitespace: '\b\t '
                   LineEnding: {'\n'  '\r'  '\r\n'}
                 CommentStyle: {}
    ConsecutiveDelimitersRule: 'split'
        LeadingDelimitersRule: 'keep'
       TrailingDelimitersRule: 'ignore'
                EmptyLineRule: 'skip'
                     Encoding: 'ISO-8859-1'

   Replacement Properties:
                  MissingRule: 'fill'
              ImportErrorRule: 'fill'
             ExtraColumnsRule: 'addvars'

   Variable Import Properties: Set types by name using setvartype
                VariableNames: {'Year', 'Month', 'DayofMonth' ... and 26 more}
                VariableTypes: {'double', 'double', 'double' ... and 26 more}
        SelectedVariableNames: {'Year', 'Month', 'DayofMonth' ... and 26 more}
              VariableOptions: Show all 29 VariableOptions 
	Access VariableOptions sub-properties using setvaropts/getvaropts
           VariableNamingRule: 'modify'

   Location Properties:
                    DataLines: [2 Inf]
            VariableNamesLine: 1
               RowNamesColumn: 0
            VariableUnitsLine: 0
     VariableDescriptionsLine: 0 
	To display a preview of the table, use preview

Examine the Type property of the variables TaxiIn and TaxiOut.

getvaropts(opts,{'TaxiIn','TaxiOut'})
ans = 
  1x2 TextVariableImportOptions array with properties:

    Name
    Type
    FillValue
    TreatAsMissing
    QuoteRule
    Prefixes
    Suffixes
    EmptyFieldRule
    WhitespaceRule

Change the type of the variables TaxiIn and TaxiOut to double.

 opts = setvartype(opts,{'TaxiIn','TaxiOut'},'double');

Specify the subset of variables to import and examine.

opts.SelectedVariableNames = {'TaxiIn','TaxiOut'};

Use the readtable function along with the options object to import the selected variables. Display a summary of the table.

T = readtable('airlinesmall.csv',opts);
summary(T)
Variables:

    TaxiIn: 123523x1 double

        Values:

            Min             0      
            Median          5      
            Max             1451   
            NumMissing      37383  

    TaxiOut: 123523x1 double

        Values:

            Min             0      
            Median          13     
            Max             755    
            NumMissing      37364
Open Live Script

Import text data as a string data type by specifying import options.

Create an options object for the file.

opts = detectImportOptions('outages.csv');

Specify which variables to import using readtable, and then show a summary. The data type of the selected variables is char.

opts.SelectedVariableNames = {'Region','Cause'};
T = readtable('outages.csv',opts);
summary(T)
Variables:

    Region: 1468x1 cell array of character vectors

    Cause: 1468x1 cell array of character vectors

Import text data as a string data type, and then create import options by specifying the TextType name-value pair.

opts = detectImportOptions('outages.csv','TextType','string');

Specify which variables to import using readtable, and then show a summary. The data type of the selected variables is now string.

opts.SelectedVariableNames = {'Region','Cause'};
T = readtable('outages.csv',opts);
summary(T)
Variables:

    Region: 1468x1 string

    Cause: 1468x1 string

Input Arguments

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Name of the file to read, specified as a character vector or string scalar.

Depending on the location of your file, filename can take on one of these forms.

Location

Form

Current folder or folder on the MATLAB path

Specify the name of the file in filename.

Example: 'myFile.txt'

File in a folder

If the file is not in the current folder or in a folder on the MATLAB path, then specify the full or relative path name in filename.

Example: 'C:\myFolder\myFile.xlsx'

Example: '\imgDir\myFile.txt'

Remote Location

If the file is stored at a remote location, then filename must contain the full path of the file specified as a uniform resource locator (URL) of the form:

scheme_name://path_to_file/my_file.ext

Based on your remote location, scheme_name can be one of the values in this table.

Remote Locationscheme_name
Amazon S3™s3
Windows Azure® Blob Storagewasb, wasbs
HDFS™hdfs

For more information, see Work with Remote Data.

Example: 's3://bucketname/path_to_file/my_file.csv'

If filename includes the file extension, then detectImportOptions determines the file format from the extension. Otherwise, you must specify the 'FileType' name-value pair to indicate the type of file.

The detectImportOptions function supports these file extensions: .txt, .dat, .csv, .xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, and .ods.

Note

File extensions .xlsb and .ods are only supported on platforms with Excel® for Windows®.

Data Types: char | string

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'FileType','spreadsheet'
Parameters

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Type of file, specified as the comma-separated pair consisting of 'FileType' and one of these values.

ValueImport Options for File
'spreadsheet'

Return a SpreadsheetImportOptions object.

'text'

Return a DelimitedTextImportOptions or FixedWidthImportOptions object depending on the layout of the text file.

'delimitedtext'

Return a DelimitedTextImportOptions object. Use this option for text files that have columns separated by delimiters.

'fixedwidth'

Return a FixedWidthImportOptions object. Use this option for text files that have columns of fixed widths.

Use the 'FileType' name-value pair argument when filename does not include the file extension, or when the extension is not one of these:

  • .txt, .dat, or .csv for text files

  • .xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, or .ods for spreadsheet files

File extensions .xlsb and .ods are only supported on platforms with Excel for Windows.

Example: 'FileType','text'

Data Types: char | string

Type for imported text data, specified as the comma-separated pair consisting of 'TextType' and either 'char' or 'string'.

  • 'char' — Import text data into MATLAB as character vectors.

  • 'string' — Import text data into MATLAB as string arrays.

Example: 'TextType','char'

Type for imported date and time data, specified as the comma-separated pair consisting of 'DatetimeType' and one of these values: 'datetime', 'text', or 'exceldatenum'. The value 'exceldatenum' is applicable only for spreadsheet files, and is not valid for text files.

ValueType for Imported Date and Time Data
'datetime'

MATLAB datetime data type

For more information, see datetime.

'text'

If 'DatetimeType' is specified as 'text', then the type for imported date and time data depends on the value specified in the 'TextType' parameter:

  • If 'TextType' is set to 'char', then the importing function returns dates as a cell array of character vectors.

  • If 'TextType' is set to 'string', then the importing function returns dates as an array of strings.

'exceldatenum'

Excel serial date numbers

A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see https://support.microsoft.com/en-us/kb/214330.

Data Types: char | string

Expected number of variables, specified as the comma-separated pair consisting of 'ExpectedNumVariables' and a positive integer. If unspecified, the importing function automatically detects the number of variables.

Data Types: single | double

Portion of the data to read from text or spreadsheet files, specified as the comma separated pair consisting of 'Range' and a character vector, string scalar, or numeric vector in one of these forms.

Ways to specify RangeDescription

Starting Cell

'Cell' or [row col]

Specify the starting cell for the data as a character vector or string scalar or a two element numeric vector.

  • Character vector or string scalar containing a column letter and row number using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

  • Two element numeric vector of the form [row col] indicating the starting row and column.

Using the starting cell, the importing function automatically detects the extent of the data by beginning the import at the start cell and ending at the last empty row or footer range.

Example: 'A5' or [5 1]

Rectangular Range

'Corner1:Corner2' or [r1 c1 r2 c2]

Specify the exact range to read using the rectangular range in one of these forms.

  • 'Corner1:Corner2' — Specify the range using Corner1 and Corner2 which are the two opposing corners that define the region to read in Excel A1 notation. For example, 'C2:N15'.

  • [r1 c1 r2 c2] — Specify the range using a four element numeric vector containing start-row, start-column, end-row, and end-column. For example, [2 3 15 13].

The importing function only reads the data contained in the specified range. Any empty fields within the specified range are imported as missing cells.

Row Range or Column Range

'Row1:Row2' or 'Column1:Column2'

Specify the range by identifying the beginning and ending rows using Excel row numbers.

Using the specified row range, the importing function automatically detects the column extent by reading from the first nonempty column to the end of the data, and creates one variable per column.

Example: '5:500'

Alternatively, specify the range by identifying the beginning and ending columns using Excel column letters or numbers.

Using the specified column range, the import function automatically detects the row extent by reading from the first nonempty row to the end of the data or the footer range.

The number of columns in the specified range must match the number specified in the ExpectedNumVariables property.

Example: 'A:K'

Starting Row Number

n

Specify the first row containing the data using the positive scalar row index.

Using the specified row index, the importing function automatically detects the extent of the data by reading from the specified first row to the end of the data or the footer range.

Example:5

Excel’s Named Range

'NamedRange'

In Excel, you can create names to identify ranges in the spreadsheet. For instance, you can select a rectangular portion of the spreadsheet and call it 'myTable'. If such named ranges exist in a spreadsheet, then the importing function can read that range using its name.

Example: 'Range','myTable'

Unspecified or Empty

''

If unspecified, the importing function automatically detects the used range.

Example: 'Range',''

Note: Used Range refers to the rectangular portion of the spreadsheet that actually contains data. The importing function automatically detects the used range by trimming any leading and trailing rows and columns that do not contain data. Text that is only white space is considered data and is captured within the used range.

Data Types: char | string | double

Number of header lines in the file, specified as the comma-separated pair consisting of 'NumHeaderLines' and a positive integer. If unspecified, the importing function automatically detects the number of header lines in the file.

Example: 'NumHeaderLines',7

Data Types: single | double

Indicator for reading the first row as variable names, specified as the comma-separated pair consisting of 'ReadVariableNames' and either true or false. If unspecified, readtable automatically detects the presence of variable names.

Indicator

Description

true

Use when the first row of the region to read contains the variable names for the table. readtable creates a variable, with the detected variable name, for each column in T.

false

Use when the first row of the region to read contains data in the table. readtable creates default variable names of the form 'Var1',...,'VarN', where N is the number of variables.

unspecified When left unspecified, the importing function automatically detects true or false and proceeds accordingly.

Data Types: logical

Flag to preserve variable names, specified as the comma-separated pair consisting of VariableNamingRule and either true, or false.

  • 'preserve' — Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.

  • 'modify' — Convert invalid variable names (as determined by the isvarname function) to valid MATLAB identifiers.

Starting in R2019b, variable names and row names can include any characters, including spaces and non-ASCII characters. Also, they can start with any characters, not just letters. Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname function). To preserve these variable names and row names, set the value of VariableNamingRule to 'preserve'.

Data Types: char | string

Indicator for reading first column as row names, specified as the comma-separated pair consisting of 'ReadRowNames' and either false or true.

Indicator

Description

false

Use when the first column of the region to read contains data, and not the row names for the table.

true

Use when the first column of the region to read contains the row names for the table.

unspecifiedWhen left unspecified, the importing function assumes false.

Data Types: logical

Procedure to manage missing data, specified as one of the values in this table.

Missing RuleBehavior
'fill'

Replace missing data with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

'error'Stop importing and display an error message showing the missing record and field.
'omitrow'Omit rows that contain missing data.
'omitvar'Omit variables that contain missing data.

Example: opts.MissingRule = 'omitrow';

Data Types: char | string

Procedure to handle import errors, specified as one of the values in this table.

Import Error RuleBehavior
'fill'

Replace the data where the error occurred with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

'error'Stop importing and display an error message showing the error-causing record and field.
'omitrow'Omit rows where errors occur.
'omitvar'Omit variables where errors occur.

Example: opts.ImportErrorRule = 'omitvar';

Data Types: char | string

Parameters for Spreadsheet Files Only

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Sheet to read from, specified as an empty character array, a character vector or string scalar containing the sheet name, or a positive scalar integer denoting the sheet index. Based on the value specified for the Sheet property, the import function behaves as described in the table.

SpecificationBehavior
'' (default)Import data from the first sheet.
NameImport data from the matching sheet name, regardless of order of sheets in the spreadsheet file.
IntegerImport data from sheet in the position denoted by the integer, regardless of the sheet names in the spreadsheet file.

Data Types: char | string | single | double

Location of data to be imported, specified as a character vector, string scalar, cell array of character vectors, string array, positive scalar integer or an N-by-2 array of positive scalar integers. Specify DataRange using one of these forms.

Specified byBehavior

'Cell' or n

Starting Cell or Starting Row

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

Using the starting cell, the importing function automatically detects the extent of the data, by beginning the import at the start cell and ending at the last empty row or footer range.

Alternatively, specify the first row containing the data using the positive scalar row index.

Using the specified row index, the importing function automatically detects the extent of the data by reading from the specified first row to the end of the data or the footer range.

Example: 'A5' or 5

'Corner1:Corner2'

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The importing function only reads the data contained in the specified range. Any empty fields within the specified range are imported as missing cells.

The number of columns must match the number specified in the NumVariables property.

Example: 'A5:K50'

'Row1:Row2' or 'Column1:Column2'

Row Range or Column Range

Specify the range by identifying the beginning and ending rows using Excel row numbers.

Using the specified row range, the importing function automatically detects the column extent by reading from the first nonempty column to the end of the data, and creates one variable per column.

Example: '5:500'

Alternatively, specify the range by identifying the beginning and ending columns using Excel column letters or numbers.

Using the specified column range, the import function automatically detects the row extent by reading from the first nonempty row to the end of the data or the footer range.

The number of columns in the specified range must match the number specified in the NumVariables property.

Example: 'A:K'

[n1 n2; n3 n4;...]

Multiple Row Ranges

Specify multiple row ranges to read with an N-by-2 array containing N different row ranges.

A valid array of multiple row ranges must:

  • Specify line ranges in an increasing order, that is the first row range specified in the array appears in the file before the other row ranges.

  • Contain only non-overlapping row ranges.

Use of Inf is only supported to indicate the last range in the numeric array specifying multiple row ranges. For example, [1 3; 5 6; 8 Inf].

Example: [1 3; 5 6; 8 Inf]

''

Unspecified or Empty

Do not fetch any data.

Example: ''

Data Types: char | string | cell | single | double

Location of row names, specified as a character vector, string scalar, positive scalar integer, or an empty character array. Specify RowNamesRange as one of the values in this table.

Specified byBehavior

'Cell'

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

The importing function identifies a name for each variable in the data.

Example: 'A5'

'Corner1:Corner2'

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The number of rows contained in RowNamesRange must match the number of data rows, and the range indicated by RowNamesRange must span only one column.

Example: 'A5:A50'

'Row1:Row2'

Row Range

Specify range by identifying the beginning and ending rows using Excel row numbers.

Row names must be in a single column.

Example: '5:50'

n

Number Index

Specify the column containing the row names using a positive scalar column index.

Example: 5

''

Unspecified or Empty

Indicate that there are no row names.

Example: ''

Data Types: char | single | double

Location of variable names, specified as a character vector, string scalar, positive scalar integer, or an empty character array. Specify VariableNamesRange as one of the values in this table.

Specified byBehavior

'Cell'

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

The importing function reads a name for each variable in the data.

Example: 'A5'

'Corner1:Corner2'

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The number of columns must match the number specified in the NumVariables property, and the range must span only one row.

Example: 'A5:K5'

'Row1:Row2'

Row Range

Specify range by identifying the beginning and ending rows using Excel row numbers.

Must be a single row.

Example: '5:5'

n

Number Index

Specify the row containing the variable names using a positive scalar row index.

Example: 5

''

Unspecified or Empty

Indicate that there are no variable names.

Example: ''

Data Types: char | single | double

Location of variable units, specified as a character vector, string scalar, positive scalar integer, or an empty character array. Specify VariableUnitsRange as one of the values in this table.

Specified byBehavior

'Cell'

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

The importing function reads a unit for each variable in the data.

Example: 'A5'

'Corner1:Corner2'

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The number of columns must match the number specified in the NumVariables property, and the range must span only one row.

Example: 'A5:K5'

'Row1:Row2'

Row Range

Specify range by identifying the beginning and ending rows using Excel row numbers.

Must be a single row.

Example: '5:5'

n

Number Index

Specify the row containing the data units using a positive scalar row index.

Example: 5

''

Unspecified or Empty

Indicate that there are no variable units.

Example: ''

Data Types: char | string | single | double

Location of variable descriptions, specified as a character vector, string scalar, positive scalar integer, or an empty character array. Specify VariableDescriptionRange as one of the values in this table.

Specified byBehavior

'Cell'

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

The importing function reads a description for each variable in the data.

Example: 'A5'

'Corner1:Corner2'

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The number of columns must match the number specified in the NumVariables property, and the range must span only one row.

Example: 'A5:K5'

'Row1:Row2'

Row Range

Specify range by identifying the beginning and ending rows using Excel row numbers.

Must be a single row.

Example: '5:5'

n

Number Index

Specify the row containing the descriptions using a positive scalar row index.

Example: 5

''

Unspecified or Empty

Indicate that there are no variable descriptions.

Example: ''

Data Types: char | string | single | double

Parameters for Text Files Only

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Field delimiter characters in a delimited text file, specified as a character vector, string scalar, cell array of character vectors, or string array.

Example: 'Delimiter','|'

Example: 'Delimiter',{';','*'}

Data Types: char | string | cell

Procedure to manage leading delimiters in a delimited text file, specified as one of the values in this table.

Leading Delimiters RuleBehavior
'keep'Keep the delimiter.
'ignore'Ignore the delimiter.
'error'Return an error and abort the import operation.

Procedure to manage trailing delimiters in a delimited text file, specified as one of the values in this table.

Leading Delimiters RuleBehavior
'keep'Keep the delimiter.
'ignore'Ignore the delimiter.
'error'Return an error and abort the import operation.

Procedure to handle consecutive delimiters in a delimited text file, specified as one of the values in this table.

Consecutive Delimiters RuleBehavior
'split'Split the consecutive delimiters into multiple fields.
'join'Join the delimiters into one delimiter.
'error'Return an error and abort the import operation.

Data Types: char | string

Field widths of variables in a fixed-width text file, specified as a vector of positive integer values. Each positive integer in the vector corresponds to the number of characters in a field that makes up the variable. The VariableWidths property contains an entry corresponding to each variable specified in the VariableNames property.

Characters to treat as white space, specified as a character vector or string scalar containing one or more characters.

Example: 'Whitespace',' _'

Example: 'Whitespace','?!.,'

End-of-line characters, specified as a character vector, string scalar, cell array of character vectors, or string array.

Example: 'LineEnding','\n'

Example: 'LineEnding','\r\n'

Example: 'LineEnding',{'\b',':'}

Data Types: char | string | cell

Character encoding scheme associated with the file, specified as the comma-separated pair consisting of 'Encoding' and 'system' or a standard character encoding scheme name.

When you do not specify any encoding, the function uses automatic character set detection to determine the encoding when reading the file.

Example: 'Encoding','system' uses the system default encoding.

Data Types: char | string

Style of comments, specified as a character vector, string scalar, cell array of character vectors, or string array.

For example, to ignore the text following a percent sign on the same line, specify CommentStyle as '%'.

Example: 'CommentStyle',{'/*'}

Data Types: char | string | cell

Output data type of duration data from text files, specified as the comma-separated pair consisting of 'DurationType' and either 'duration' or 'text'.

ValueType for Imported Duration Data
'duration'

MATLAB duration data type

For more information, see duration.

'text'

If 'DurationType' is specified as 'text', then the type for imported duration data depends on the value specified in the 'TextType' parameter:

  • If 'TextType' is set to 'char', then the importing function returns duration data as a cell array of character vectors.

  • If 'TextType' is set to 'string', then the importing function returns duration data as an array of strings.

Data Types: char | string

Procedure to handle extra columns in the data, specified as one of the values in this table.

Extra Columns RuleBehavior
'addvars'

To import extra columns, create new variables. If there are N extra columns, then import new variables as 'ExtraVar1', 'ExtraVar2',..., 'ExtraVarN'.

NOTE: The extra columns are imported as text with data typechar.

'ignore'Ignore the extra columns of data.
'wrap'Wrap the extra columns of data to new records. This action does not change the number of variables.
'error'Display an error message and abort the import operation.

Data Types: char | string

Text to interpret as missing data, specified as a character vector, string scalar, cell array of character vectors, or string array.

When the importing function finds missing instances, it uses the specification in the MissingRule property to determine the appropriate action.

Example: 'TreatAsMissing',{'NA','TBD'} instructs the importing function to treat any occurrence of NA or TBD as a missing fields.

Data Types: char | string | cell

Locale for reading dates, specified as the comma-separated pair consisting of 'DateLocale' and a character vector or a string scalar of the form xx_YY, where:

  • YY is an uppercase ISO 3166-1 alpha-2 code indicating a country.

  • xx is a lowercase ISO 639-1 two-letter code indicating a language.

For a list of common values for the locale, see the Locale name-value pair argument for the datetime function.

When using the %D format specifier to read text as datetime values, use DateLocale to specify the locale in which the importing function should interpret month and day-of-week names and abbreviations.

If you specify the DateLocale argument in addition to opts the import options, then the importing function uses the specified value for the DateLocale argument, overriding the locale defined in the import options.

Example: 'DateLocale','ja_JP'

Characters that indicate the thousands grouping in numeric variables, specified as a character vector or string scalar. The thousands grouping characters act as visual separators, grouping the number at every three place values. The importing function uses the characters in the ThousandsSeparator property to interpret the numbers being imported.

Data Types: char | string

Characters indicating the decimal separator in numeric variables, specified as a character vector or string scalar. The importing function uses the DecimalSeparator property to distinguish the integer part of a number from the decimal part.

When converting to integer data types, numbers with a decimal part are rounded to the nearest integer.

Data Types: char | string

Remove nonnumeric characters from a numeric variable, specified as a logical true or false.

Data Types: logical

Output data type of hexadecimal data, specified as the comma-separated pair consisting of 'HexType' and one of the values listed in the table.

The input file represents hexadecimal values as text, using either 0x or 0X as a prefix and the characters 0-9, a-f, and A-F as digits. (Uppercase and lowercase letters represent the same digits—for example, '0xf' and '0xF' both represent 15.)

The importing function converts the hexadecimal values to the data type specified by the value of 'HexType'.

Value of 'HexType'

Data Type of Output Table Variables

'auto'

data type detected automatically

'text'

unaltered input text

'int8'

8-bit integer, signed

'int16'

16-bit integer, signed

'int32'

32-bit integer, signed

'int64'

64-bit integer, signed

'uint8'

8-bit integer, unsigned

'uint16'

16-bit integer, unsigned

'uint32'

32-bit integer, unsigned

'uint64'

64-bit integer, unsigned

Example: 'HexType','uint16' converts text representing hexadecimal values (such as '0xFF') to unsigned 16-bit integers (such as 255) in the output table.

Data Types: char | string

Output data type of binary data, specified as the comma-separated pair consisting of 'BinaryType' and one of the values listed in the table.

The input file represents binary values as text, using either 0b or 0B as a prefix and the characters 0 and 1 as digits.

The importing function converts the binary values to the data type specified by the value of 'BinaryType'.

Value of 'BinaryType'

Data Type of Output Table Variables

'auto'

data type detected automatically

'text'

unaltered input text

'int8'

8-bit integer, signed

'int16'

16-bit integer, signed

'int32'

32-bit integer, signed

'int64'

64-bit integer, signed

'uint8'

8-bit integer, unsigned

'uint16'

16-bit integer, unsigned

'uint32'

32-bit integer, unsigned

'uint64'

64-bit integer, unsigned

Example: 'BinaryType','uint16' converts text representing binary values (such as '0b11111111') to unsigned 16-bit integers (such as 255) in the output table.

Data Types: char | string

Output Arguments

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Import options for the specified file, returned as a SpreadsheetImportOptions object or a DelimitedTextImportOptions object. The type of options object depends on the type of file specified. For text files (.txt, .dat, or .csv), the detectImportOptions function returns a DelimitedTextImportOptions or FixedWidthImportOptions object. For spreadsheet files (.xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, or .ods), the detectImportOptions function returns a SpreadsheetImportOptions object.

Tips

  • Updating Property Values After Creating the Import Options Object: Use of dot notation to update the properties of the import options object created by detecImportOptions is not recommended. Setting properties using dot notation does not lead to a re-detection of all the import options for the file. Therefore, to update and re-detect all the properties, you must specify the new values by using name-value pairs. For example, update the value for the ConsecutiveDelimitersRule property and re-detect the import options as follows. 

    opts = detectImportOptions(__,'ConsecutiveDelimitersRule','join')

See Also

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Topics

Introduced in R2016b

MATLAB Documentation

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