strncmpi - Compare first n characters of strings

(case insensitive) - MATLAB (original) (raw)

Compare first n characters of strings (case insensitive)

Syntax

Description

[tf](#bvjtblc-1-tf) = strncmpi([s1,s2](#bvjtblc-1-s1s2),[n](#bvjtblc-1-n)) compares up to n characters of s1 ands2, ignoring any differences in letter case, and returnstrue(1) if the two are identical andfalse(0) otherwise. Text is considered identical if the content of each is the same up to the end or the firstn characters, whichever comes first, ignoring case. The return result tf is of data typelogical.

The first two input arguments can be any combination of string arrays, character vectors, and cell arrays of character vectors.

example

Examples

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Create two character vectors. Compare the first four characters of each, ignoring case.

s1 = 'DATA.TAR.GZ'; s2 = 'data-samples.xls';

tf = strncmpi(s1,s2,4)

tf is 1 because s1 starts with 'DATA', and s2 starts with 'data'.

Create a string array that contains names. Find the names that start with 'JEAN', ignoring case.

s1 = ["Jacques"; "Jean"; "Jeanne"; "Jean-Luc"; "Julie"]; s2 = "JEAN";

tf = strncmpi(s1,s2,4)

tf = 5×1 logical array

0 1 1 1 0

tf is 1 for all names whose first four characters match 'JEAN' when you ignore case.

Alternatively, you can use the startsWith function.

tf = startsWith(s1,s2,'IgnoreCase',true)

tf = 5×1 logical array

0 1 1 1 0

Input Arguments

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Input text, with each input specified as a character vector, a character array, a cell array of character vectors, or a string array. The order of the inputs does not affect the comparison results.

If both s1 and s2 are string arrays or cell arrays of character vectors, then s1 and s2 must be the same size, unless one of them is scalar.
If both s1 and s2 are character arrays with multiple rows, then s1 and s2 can have different numbers of rows.
When comparing a nonscalar cell array of character vectors or string array to a multirow character array, the cell array or string array must be a column vector with the same number of rows as the character array.

Data Types: char | cell | string

Maximum number of characters to compare, specified as an integer.

If n is 0, thenstrncmpi always returnstrue(1). By convention, the zeroth character of a character vector or a string scalar is always '', a0-by-0 character array.
If n is less than 0, thenstrncmpi treats it as0.

Output Arguments

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True or false result, returned as true(1) orfalse(0) or as alogical array.

If each input is either a string scalar or a character vector, then tf is a scalar.
If at least one input is either a string array or a cell array of character vectors, then tf is an array the same size as the input array.
If one input is a character array with multiple rows, and the other input is either a scalar cell or a string scalar, thentf is ann-by-1 array, wheren is the number of rows in the character array.
If both inputs are character arrays, tf is a scalar.

Tips

The strncmpi function is intended for comparison of text. If used on numeric arrays, strncmpi always returnsfalse(0).
For case-sensitive text comparison, use strncmp instead of strncmpi.
Although strncmpi shares a name with a C function, it does not follow the C language convention of returning 0 when the text inputs match.

Extended Capabilities

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Thestrncmpi function fully supports tall arrays. For more information, see Tall Arrays.

Usage notes and limitations:

Enumeration inputs are not supported.
Input values from the char class must be in the range 0-127.
When one input is a cell array and the other input is a character array, the character array must be a compile-time row vector.

Version History

Introduced before R2006a