matlab.lang.makeValidName

Construct valid MATLAB identifiers from input strings

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Syntax

N = matlab.lang.makeValidName(S)
N = matlab.lang.makeValidName(S,Name,Value)
[N, modified] = matlab.lang.makeValidName(___)

Description

N = matlab.lang.makeValidName(S) constructs valid MATLAB® identifiers, N, from input strings, S. The makeValidName function does not guarantee the strings in N are unique.

A valid MATLAB identifier is a character vector of alphanumerics (A–Z, a–z, 0–9) and underscores, such that the first character is a letter and the length of the character vector is less than or equal to namelengthmax.

makeValidName deletes any whitespace characters before replacing any characters that are not alphanumerics or underscores. If a whitespace character is followed by a lowercase letter, makeValidName converts the letter to the corresponding uppercase character.

example

N = matlab.lang.makeValidName(S,Name,Value) includes additional options specified by one or more Name,Value pair arguments.

example

[N, modified] = matlab.lang.makeValidName(___) returns a logical array, modified, indicating modified elements. You can use this syntax with any of the input arguments of the previous syntaxes.

example

Examples

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Open Live Script
S = {'Item_#','Price/Unit','1st order','Contact'};
N = matlab.lang.makeValidName(S)
N = 1×4 cell
    {'Item__'}    {'Price_Unit'}    {'x1stOrder'}    {'Contact'}

In the first and second elements, makeValidName replaced the invalid characters (# and /), with underscores. In the third element, makeValidName appended a prefix because the character vector does not begin with a letter, deleted the empty space, and capitalized the character following the deleted space.

Open Live Script

Replace invalid characters with the corresponding hexadecimal representation. 

S = {'Item_#','Price/Unit','1st order','Contact'};
N = matlab.lang.makeValidName(S,'ReplacementStyle','hex')
N = 1×4 cell
    {'Item_0x23'}    {'Price0x2FUnit'}    {'x1stOrder'}    {'Contact'}

In the first and second elements, makeValidName replaced the invalid characters (# and /), with their hexadecimal representation. In the third element, makeValidName appended a prefix because the character vector does not begin with a letter, deleted the empty space, and capitalized the character following the deleted space.

Delete invalid characters. 

N = matlab.lang.makeValidName(S,'ReplacementStyle','delete')
N = 1×4 cell
    {'Item_'}    {'PriceUnit'}    {'x1stOrder'}    {'Contact'}

makeValidName deleted the invalid characters (# and /). In the third element, makeValidName appended a prefix because the character vector does not begin with a letter, deleted the empty space, and capitalized the character following the deleted space.

Open Live Script
S = {'1stMeasurement','2ndMeasurement','Control'};
N = matlab.lang.makeValidName(S,'Prefix','m_')
N = 1×3 cell
    {'m_1stMeasurement'}    {'m_2ndMeasurement'}    {'Control'}

Only the elements that do not start with a letter are prepended with a prefix.

Open Live Script
S = {'a%name', 'name_1', '2_name'};
[N, modified] = matlab.lang.makeValidName(S)
N = 1×3 cell
    {'a_name'}    {'name_1'}    {'x2_name'}


modified = 1×3 logical array

   1   0   1

makeValidName did not modify the second element.

Input Arguments

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Input strings, specified as a character vector, cell array of character vectors, or string array.

Name-Value Arguments

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Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: 'ReplacementStyle','delete' deletes invalid characters.

Replacement style, specified as 'underscore', 'delete', or 'hex'. The value controls how MATLAB replaces nonalphanumeric characters. For all values of ReplacementStyle, MATLAB deletes whitespace characters and changes a lowercase letter following a whitespace to uppercase.

ReplacementStyle ValueDescription
'underscore' (default)Replaces all characters that are not alphanumerics or underscores with underscores. 'underscore'.
'hex'Replaces each character that is not an alphanumeric or underscore with its corresponding hexadecimal representation. 'hex'.
'delete'Deletes all characters that are not alphanumerics or underscores. 'delete'.

Characters to prefix to inputs that do not begin with a letter after makeValidName replaces nonalphanumeric characters, specified as a character vector or string scalar. For example, by default, makeValidName prefixes characters to an input '*hello' because, after it replaces nonalphanumeric characters, the input does not begin with a letter ('_hello'). However, if you specify a replacement style that deletes nonalphanumeric characters, makeValidName does not prefix characters. After it replaces nonalphanumeric characters, the input begins with a letter ('hello').

A valid prefix must meet the following conditions.

  • Start with a letter.

  • Contain only alphanumeric characters and underscores.

  • Not be a MATLAB keyword.

  • Not be longer than the value of namelengthmax.

Output Arguments

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Valid MATLAB identifiers, returned as a character vector, cell array of character vectors, or string array. The output has the same number of dimensions as the input, S.

Indicator of modified elements, returned as a logical scalar or array and having the same number of dimensions as the input, S. A value of 1 (true) indicates that makeValidName modified the input in the corresponding location. A value of 0 (false) indicates that makeValidName did not need to modify the input in the corresponding location.

Tips

  • To ensure that input values are valid and unique, use matlab.lang.makeUniqueStrings after matlab.lang.makeValidName.

    S = {'my.Name','my_Name','my_Name'};
validValues = matlab.lang.makeValidName(S)
validUniqueValues = matlab.lang.makeUniqueStrings(validValues,{},...
    namelengthmax)
    validValues = 

    'my_Name'    'my_Name'    'my_Name'


validUniqueValues = 

    'my_Name'    'my_Name_1'    'my_Name_2'

  • To customize an invalid character replacement, first use functions such as strrep or regexprep to convert to valid characters. For example, convert '@' characters in S to 'At' using strrep(S,'@','At'). Then, use matlab.lang.makeValidName to ensure that all characters in S are valid.

Version History

Introduced in R2014a

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See Also

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