strcat including space (i.e, ' ')

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R P
R P on 11 Jun 2011
Answered: Jy·Li on 25 May 2023
I have to concatenate words, including spaces
Ex. a='word1'; b='word2';c=strcat(a,' ',b);
I need 'word1 word2', however, the value on c is 'word1word2'
Can you help me?

Accepted Answer

Walter Roberson
Walter Roberson on 11 Jun 2011
Edited: MathWorks Support Team on 8 Nov 2018
To include spaces when concatenating character vectors, use square brackets.
a = 'word1';
b = 'word2';
c = [a ' ' b]
The “ strcat ” function ignores trailing whitespace characters in character vectors. However, “strcat” preserves them in cell arrays of character vectors or string arrays.
a = {'word1'};
b = {'word2'};
c = strcat(a,{' '},b)
You also can use the “plus” operator to combine strings. Starting in R2017a, use double quotes to create strings. For more information on strings, see the “ string ” data type.
a = "word1";
b = "word2";
c = a + " " + b
  6 Comments
Captain Karnage
Captain Karnage on 26 Aug 2022
Edited: Voss on 26 Aug 2022
FYI for anyone else reading, I had a cell array of strings and I wanted to concatenate the same string (with a space in it) to each of the strings in the cell array (no spaces in these strings). The square bracket (first) method of course doesn't work, neither does the "plus" operator (third/last) method for that. However, the "strcat" using a single cell array with a space (2nd/middle above) method does work.
To specifically show an example:
a = 'Addme';
b = { 'to', 'each', 'one', 'of', 'these', 'words', 'with', 'a', 'space'};
c = strcat(a,{' '},b)
c = 1×9 cell array
{'Addme to'} {'Addme each'} {'Addme one'} {'Addme of'} {'Addme these'} {'Addme words'} {'Addme with'} {'Addme a'} {'Addme space'}
Walter Roberson
Walter Roberson on 26 Aug 2022
Edited: Walter Roberson on 26 Aug 2022
a = 'Addme';
b = { 'to', 'each', 'one', 'of', 'these', 'words', 'with', 'a', 'space'};
strjoin([a, b])
ans = 'Addme to each one of these words with a space'
a + " " + b
ans = 1×9 string array
"Addme to" "Addme each" "Addme one" "Addme of" "Addme these" "Addme words" "Addme with" "Addme a" "Addme space"

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More Answers (4)

Paulo Silva
Paulo Silva on 11 Jun 2011
c=[a ' ' b]
strcat ignores trailing ASCII white space characters and omits all such characters from the output. White space characters in ASCII are space, newline, carriage return, tab, vertical tab, or form-feed characters, all of which return a true response from the MATLAB isspace function. Use the concatenation syntax [s1 s2 s3 ...] to preserve trailing spaces. strcat does not ignore inputs that are cell arrays of strings.
  2 Comments
Daniel Foose
Daniel Foose on 23 Feb 2018
This is better than the accepted answer because it keeps the type the same. The accepted answer returns a cell with a string in it (which is different from a string). This answer returns a string.
Walter Roberson
Walter Roberson on 23 Feb 2018
The accepted answer returns a cell with a character vector in it. Strings did not exist in R2011a. If strings were being used then you would use a different approach:
>> a = "word1"; b = "word2"; a + " " + b
ans =
"word1 word2"
This requires R2017a or later. For R2016b,
>> a = string('word1'); b = string('word2'); a + ' ' + b
and before R2016b strings did not exist.

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Jy·Li
Jy·Li on 25 May 2023
c=strcat(a,32,b); % the unicode value of ' ' is 32

Usman Nawaz
Usman Nawaz on 6 Sep 2020
use double quotes instead of single quotes, worked for me.
  1 Comment
Walter Roberson
Walter Roberson on 6 Sep 2020
That can be useful, but the output would be a string() object instead of a character vector. string() objects can be useful, but they need slightly different handling than character vectors.
string() objects became available in R2016b; using double-quotes to indicate string objects became available in R2017a.

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R P
R P on 11 Jun 2011
Thank you, Walter
  3 Comments
Walter Roberson
Walter Roberson on 11 Jun 2011
>> strcat({'word1'},{' '},{'word2'})
ans =
'word1 word2'
You can dereference this or cell2mat it if you want the string itself as output.
Jan
Jan on 11 Jun 2011
@Walter: CELL2MAT is not efficient here. S{1} is nicer.

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