finding common prefix of array of strings

Question

I have an array like this:

$sports = array(
\'Softball - Counties\',
\'Softball - Eastern\',
\'Softball - North Harbour\',
\'Softball - South\',
\'Softball -         


        

Answer 1

How about something like this? It can be further optimised by not having to check the lengths of the strings if we can use the null terminating character (but I am assuming python strings have length cached somewhere?)

def find_common_prefix_len(strings):
    """
    Given a list of strings, finds the length common prefix in all of them.
    So
    apple
    applet
    application
    would return 3
    """
    prefix          = 0
    curr_index      = -1
    num_strings     = len(strings)
    string_lengths  = [len(s) for s in strings]
    while True:
        curr_index  += 1
        ch_in_si    = None
        for si in xrange(0, num_strings):
            if curr_index >= string_lengths[si]:
                return prefix
            else:
                if si == 0:
                    ch_in_si = strings[0][curr_index]
                elif strings[si][curr_index] != ch_in_si:
                    return prefix
        prefix += 1