Programming

Cell Arrays of Strings

Creating strings in a regular MATLAB array requires that all strings in the array be of the same length. This often means that you have to pad blanks at the end of strings to equalize their length. However, another type of MATLAB array, the cell array, can hold different sizes and types of data in an array without padding. Cell arrays provide a more flexible way to store strings of varying length.

For details on cell arrays, see Cell Arrays.

Converting to a Cell Array of Strings

The cellstr function converts a character array into a cell array of strings. Consider the character array

• data = ['Allison Jones';'Development  ';'Phoenix      '];
  

Each row of the matrix is padded so that all have equal length (in this case, 13 characters).

Now use cellstr to create a column vector of cells, each cell containing one of the strings from the data array:

• celldata = cellstr(data)
  celldata = 
      'Allison Jones'
      'Development'
      'Phoenix'
  

Note that the cellstr function strips off the blanks that pad the rows of the input string matrix:

• length(celldata{3})
  ans =
      7
  

The iscellstr function determines if the input argument is a cell array of strings. It returns a logical 1 (true) in the case of celldata:

• iscellstr(celldata)
  ans =
       1
  

Use char to convert back to a standard padded character array:

• strings = char(celldata)
  strings =
     Allison Jones
     Development
     Phoenix
  
  length(strings(3,:))
  ans =
      13
  

Functions for Cell Arrays of Strings

This table describes the MATLAB functions for working with cell arrays.

Function	Description
cellstr	Convert a character array to a cell array of strings.
char	Convert a cell array of strings to a character array.
deblank	Remove trailing blanks from a string.
iscellstr	Return true for a cell array of strings.
sort	Sort elements in ascending or descending order.
strcat	Concatenate strings.
strcmp	Compare strings.
strmatch	Find possible matches for a string.

You can also use the following set functions with cell arrays of strings.

Function	Description
intersect	Set the intersection of two vectors.
ismember	Detect members of a set.
setdiff	Return the set difference of two vectors.
setxor	Set the exclusive OR of two vectors.
union	Set the union of two vectors.
unique	Set the unique elements of a vector.

Characters and Strings

String Comparisons

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