6.3.4 Cell Arrays of Strings

One common use of cell arrays is to store multiple strings in the same variable. It is also possible to store multiple strings in a character matrix by letting each row be a string. This, however, introduces the problem that all strings must be of equal length. Therefore, it is recommended to use cell arrays to store multiple strings. For cases, where the character matrix representation is required for an operation, there are several functions that convert a cell array of strings to a character array and back. char and strvcat convert cell arrays to a character array (see Concatenating Strings), while the function cellstr converts a character array to a cell array of strings:

a = ["hello"; "world"];
c = cellstr (a)
     ⇒ c =
         {
           [1,1] = hello
           [2,1] = world
         }

: cstr = cellstr (strmat) ¶

Create a new cell array object from the elements of the string array strmat.

Each row of strmat becomes an element of cstr. Any trailing spaces in a row are deleted before conversion.

To convert back from a cellstr to a character array use char.

See also: cell, char.

One further advantage of using cell arrays to store multiple strings is that most functions for string manipulations included with Octave support this representation. As an example, it is possible to compare one string with many others using the strcmp function. If one of the arguments to this function is a string and the other is a cell array of strings, each element of the cell array will be compared to the string argument:

c = {"hello", "world"};
strcmp ("hello", c)
     ⇒ ans =
        1   0

The following string functions support cell arrays of strings: char, strvcat, strcat (see Concatenating Strings), strcmp, strncmp, strcmpi, strncmpi (see Searching in Strings), str2double, deblank, strtrim, strtrunc, strfind, strmatch, , regexp, regexpi (see String Operations) and str2double (see Converting Strings).

The function iscellstr can be used to test if an object is a cell array of strings.

: tf = iscellstr (cell) ¶

Return true if every element of the cell array cell is a character string.

See also: ischar, isstring.