strtrim

Remove leading and trailing whitespace from strings

Syntax

newStr = strtrim(str)

Description

Note

strip is recommended over strtrim because it provides greater flexibility and allows vectorization. For additional information, see Alternative Functionality.

newStr = strtrim(str) removes leading and trailing whitespace characters from str and returns the result as newStr. However, strtrim does not remove significant whitespace characters. For example, strtrim removes leading and trailing space and tab characters, but does not remove the nonbreaking space character, char(160).

Examples

Remove Leading Whitespace from Character Vector

Create a character vector with spaces and a tab character as leading whitespace.

chr = sprintf('  \t   Remove    leading whitespace')

chr = 
'  	   Remove    leading whitespace'

Remove the leading tab and spaces.

newChr = strtrim(chr)

newChr = 
'Remove    leading whitespace'

strtrim removes the leading whitespace characters, but not the whitespace between other characters.

Remove Leading and Trailing Spaces from String Array

Create a string array.

str = ["   Gemini    ","   Apollo    ";
       "   ISS       ","   Skylab    "]

str = 2x2 string
    "   Gemini    "    "   Apollo    "
    "   ISS       "    "   Skylab    "

Remove leading and trailing whitespace with the strtrim function.

newStr = strtrim(str)

newStr = 2x2 string
    "Gemini"    "Apollo"
    "ISS"       "Skylab"

Remove Leading and Trailing Whitespace from Cell Array

Remove the leading and trailing whitespace from all the character vectors in a cell array and display them.

chr = {'     Trim leading whitespace';
       'Trim trailing whitespace     '}

chr = 2x1 cell
    {'     Trim leading whitespace' }
    {'Trim trailing whitespace     '}

newChr = strtrim(chr)

newChr = 2x1 cell
    {'Trim leading whitespace' }
    {'Trim trailing whitespace'}

Keep Nonbreaking Space Character

Create a character vector that includes the nonbreaking space character, char(160), as a trailing whitespace character.

chr = '     Keep nonbreaking space';
chr = [chr char(160) '     '];

Display chr between | symbols to show the leading and trailing whitespace.

['|' chr '|']

ans = 
'|     Keep nonbreaking space      |'

Remove the leading and trailing whitespace characters.

newChr = strtrim(chr);

Display newChr between | symbols. strtrim removes the space characters but leaves the nonbreaking space at the end of newChr.

['|' newChr '|']

ans = 
'|Keep nonbreaking space |'

Input Arguments

str — Input text

character array | cell array of character arrays | string array

Input text, specified as a character array or as a cell array of character arrays, or a string array.

Algorithms

strtrim does not remove significant whitespace characters.

This table shows the most common characters that are significant whitespace characters and their descriptions. For more information, see Whitespace character.

Significant Whitespace Character	Description
char(133)	Next line
char(160)	Nonbreaking space
char(8199)	Figure space
char(8239)	Narrow no-break space

Alternative Functionality

Update code that makes use of strtrim to use strip instead. For example:

Not Recommended	Recommended
str = " test "; newStr = strtrim(str) newStr = "test"	str = " test "; newStr = strip(str) newStr = "test"

Extended Capabilities

Tall Arrays

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

The strtrim 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:

• Input text must be string scalar or a character array.

• Input values must be in the range 0–127.

• Generated code returns an empty output as a 1-by-0 character array.

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

Distributed Arrays

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

Usage notes and limitations:

• str must be a string array or cell array of character vectors.

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

Version History

Introduced before R2006a