matlab.lang.makeUniqueStrings

Construct unique strings from input strings

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Syntax

  • U = matlab.lang.makeUniqueStrings(S)
    example
  • U = matlab.lang.makeUniqueStrings(S,excludedStrings)
    example
  • U = matlab.lang.makeUniqueStrings(S,whichStringsIdx)
    example
  • U = matlab.lang.makeUniqueStrings(S,___, maxStringLength)
    example
  • [U, modified] = matlab.lang.makeUniqueStrings(___)
    example

Description

example

U = matlab.lang.makeUniqueStrings(S) constructs unique character vectors, U, from input character vectors, S, by appending an underscore and a number to duplicates.

example

U = matlab.lang.makeUniqueStrings(S,excludedStrings) constructs character vectors that are unique within U and with respect to excludedStrings. The makeUniqueStrings function does not check excludedStrings for uniqueness.

example

U = matlab.lang.makeUniqueStrings(S,whichStringsIdx) specifies the subset of S to make unique within the entire set. makeUniqueStrings makes the character vectors in S(whichStringsIdx) unique among themselves and with respect to the remaining character vectors. makeUniqueStrings returns the remaining character vectors unmodified in U. Use this syntax when you have an array of character vectors, and need to check that only some elements of the array are unique.

example

U = matlab.lang.makeUniqueStrings(S,___, maxStringLength) specifies the maximum length, maxStringLength, of character vectors in U. If makeUniqueStrings cannot make elements in S unique without exceeding maxStringLength, it returns an error. You can use this syntax with any of the input arguments of the previous syntaxes.

example

[U, modified] = matlab.lang.makeUniqueStrings(___) returns a logical array, modified, indicating modified character vectors.

Examples

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Open Script

Create a cell array of names and make each element unique.

S = {'John' 'Sue' 'Nick' 'John' 'Campion' 'John' 'Jason'};
U = matlab.lang.makeUniqueStrings(S)

U =

  1×7 cell array

    'John'    'Sue'    'Nick'    'John_1'    'Campion'    'John_2'    'Jason'

The makeUniqueStrings function appends the duplicate names in elements 3 and 5 with underscores and incrementing numbers.

Open Script

Without specifying excluded values, make the character vectors in U unique.

S = {'John' 'Sue' 'Nick' 'John' 'Campion' 'John' 'Jason'};
U = matlab.lang.makeUniqueStrings(S)

U =

  1×7 cell array

    'John'    'Sue'    'Nick'    'John_1'    'Campion'    'John_2'    'Jason'

Specify that the character vector, 'Nick', should be excluded from the output.

U = matlab.lang.makeUniqueStrings(S, 'Nick')

U =

  1×7 cell array

    'John'    'Sue'    'Nick_1'    'John_1'    'Campion'    'John_2'    'Jason'

makeUniqueStrings excludes 'Nick' from U and instead modifies the first duplicate, found in element 3, to be 'Nick_1'.

Exclude workspace variables from the unique cell array.

Sue = 42;
U = matlab.lang.makeUniqueStrings(S, who)

U =

  1×7 cell array

    'John'    'Sue_1'    'Nick'    'John_1'    'Campion'    'John_2'    'Jason'

Since 'Sue' exists in the workspace, makeUniqueStrings makes this character vector unique by appending an underscore and number.

Open Script

Create an array of character vectors and make only the first four elements unique.

S = {'quiz' 'quiz' 'quiz' 'exam' 'quiz' 'exam'};
U = matlab.lang.makeUniqueStrings(S, 1:4)

U =

  1×6 cell array

    'quiz_1'    'quiz_2'    'quiz_3'    'exam_1'    'quiz'    'exam'

The first four elements in U are unique among themselves, and among the remaining character vectors in elements 5 and 6 ('quiz' and 'exam'). Alternatively, you can use a logical array instead of a range of linear indices to achieve the same results: U = matlab.lang.makeUniqueStrings(S, [true true true true false false]) or U = matlab.lang.makeUniqueStrings(S, logical([1 1 1 1 0 0])).

Append a duplicate 'quiz' onto the end of S and make the first four elements unique.

S{end+1} = 'quiz'
U = matlab.lang.makeUniqueStrings(S, 1:4)

S =

  1×7 cell array

    'quiz'    'quiz'    'quiz'    'exam'    'quiz'    'exam'    'quiz'


U =

  1×7 cell array

    'quiz_1'    'quiz_2'    'quiz_3'    'exam_1'    'quiz'    'exam'    'quiz'

The character vectors that makeUniqueStrings checks are still unique among themselves and among the remaining elements. Since makeUniqueStrings does not check any elements after element 4, duplicate character vectors remain.

Open Script

Create an array from S where the first three elements are unique and the maximum length of each string is 5.

S = {'sampleData' 'sampleData' 'sampleData' 'sampleData'};
U = matlab.lang.makeUniqueStrings(S, 1:3, 5)

U =

  1×4 cell array

    'sampl'    'sam_1'    'sam_2'    'sampleData'

The first element is truncated to 5 characters. The second and third elements are truncated to 3 characters to allow makeUniqueStrings to append an underscore and number, and still not exceed 5 characters.

Open Script
S = {'a%name', 'name_1', '2_name'};
[N, modified] = matlab.lang.makeValidName(S)

N =

  1×3 cell array

    '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 or cell array of character vectors.

Character vectors to exclude from U, specified as a character vector or cell array of character vectors.

Example: 'dontDuplicateThis', {'excludeS1','excludeS2'}, who

Subset of character vectors, S, to make unique within the entire set, specified as a range of linear indices or as a logical array with the same size and shape as S. If there are duplicates in S, the makeUniqueStrings function only modifies those specified by whichStringsIdx.

If whichStringsIdx is a logical array, character vectors are checked for uniqueness when the array element in the same position has a value of true.

Example: 1:5, logical([1 0 1]), [true false true]

Maximum length of output character vectors in U, specified as an integer. If makeUniqueStrings cannot make elements in S unique without exceeding maxStringLength, it returns an error.

Output Arguments

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Unique character vectors, returned as a character vector or cell array of character vectors. The output has the same dimension as the input, S.

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

More About

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Tips

  • To ensure character vectors are valid and unique, use matlab.lang.makeValidName before matlab.lang.makeUniqueStrings.

    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'

See Also

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Introduced in R2014a

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