strcmp

Compare strings

Syntax

tf = strcmp(s1,s2)

Description

tf = strcmp(s1,s2) compares s1 and s2 and returns 1 (true) if the two are identical and 0 (false) otherwise. Text is considered identical if the size and content of each are the same. The return result tf is of data type logical.

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

Examples

Compare Two Character Vectors

Compare two different character vectors.

s1 = 'Yes';
s2 = 'No';
tf = strcmp(s1,s2)

tf = logical
   0

strcmp returns 0 because s1 and s2 are not equal.

Compare two equal character vectors.

s1 = 'Yes';
s2 = 'Yes';
tf = strcmp(s1,s2)

tf = logical
   1

strcmp returns 1 because s1 and s2 are equal.

Find Text in Cell Array

Find the word 'upon' in a cell array of character vectors.

s1 = 'upon';
s2 = {'Once','upon';
      'a','time'};
tf = strcmp(s1,s2)

tf = 2x2 logical array

   0   1
   0   0

There is only one occurrence of s1 in array s2, and it occurs at element s2(1,2).

Compare Two Cell Arrays of Character Vectors

Compare each element in two cell arrays of character vectors.

s1 = {'Time','flies','when';
      'you''re','having','fun.'};
s2 = {'Time','drags','when';
      'you''re','anxiously','waiting.'};
tf = strcmp(s1,s2)

tf = 2x3 logical array

   1   0   1
   1   0   0

There are three instances of equal elements in s1 and s2. These are 'Time' at indices (1,1), 'when' at indices (1,3), and 'you''re' at indices (2,1).

Compare String Arrays

Starting in R2017a, you can create strings using double quotes. Compare string arrays using strcmp.

s1 = ["A","bc";
      "def","G"];
s2 = ["B","c";
      "def","G"];

tf = strcmp(s1,s2)

tf = 2x2 logical array

   0   0
   1   1

You can compare and sort string arrays with relational operators, just as you can with numeric arrays.

Use == to determine which elements of two string arrays are equal.

s1 == s2

ans = 2x2 logical array

   0   0
   1   1

Use < to determine which elements of s1 are less than the corresponding elements of s2 according to ASCII dictionary order.

s1 < s2

ans = 2x2 logical array

   1   1
   0   0

Input Arguments

s1,s2 — Input text

character vector | character array | cell array of character vectors | string array

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 a 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

Output Arguments

tf — True or false result

1 | 0 | logical array

True or false result, returned as a 1 or 0 of data type logical.

• If each input is either a string scalar, scalar cell, 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, then tf is an n-by-1 array, where n is the number of rows in the character array.

• If both inputs are character arrays, tf is a scalar.

Tips

• The strcmp function is intended for comparison of text. If used on unsupported data types, strcmp always returns 0.

• For case-insensitive text comparison, use strcmpi instead of strcmp.

• Although strcmp shares a name with a C function, it does not follow the C language convention of returning 0 when the text inputs match.

• With string arrays, you can use relational operators (==, ~=, <, >, <=, >=) instead of strcmp. You can compare and sort string arrays just as you can with numeric arrays.

Extended Capabilities

Tall Arrays

Calculate with arrays that have more rows than fit in memory.

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

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• Enumeration inputs are not supported.

• 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.

• When both inputs are empty character arrays that have different sizes, the generated code returns true.

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

Usage notes and limitations:

• Inputs must be string arrays or cell arrays of character vectors.

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).