How can I get the length of an array in awk?

Question

This command

echo \"hello world\" | awk \'{split($0, array, \" \")} END{print length(array) }\'

does not work for me and gives this error m

Answer 1

Mr. Ventimiglia's function requires a little adjustment to do the work (see the semicolon in for statement):

function alen(a, i) {
    for(i in a);
    return i
}

But don't work all the cases or times. That is because the manner that awk store and "see" the indexes of the arrays: they are associative and no necessarily contiguous (like C.) So, i does not return the "last" element.

To resolve it, you need to count:

function alen(a, i, k) {
    k = 0
    for(i in a) k++
    return k
}

And, in this manner, take care other index types of "unidimensional" arrays, where the index maybe an string. Please see: http://docstore.mik.ua/orelly/unix/sedawk/ch08_04.htm. For "multidimensional" and arbitrary arrays, see http://www.gnu.org/software/gawk/manual/html_node/Walking-Arrays.html#Walking-Arrays.