extract words separated by whitespace from string
out = strword(str, idx, {last})
Input:
str String input.
idx indexes of the words to be extracted.
last If true, the last word is given if idx contains an element
larger than the word count, if flase an empty string.
Default is false.
Output:
out Cell contains the extracted words in the order idx is give.
Example:
strword(' one two three four',[4 1])
the output will be: {'four' 'one'}.