PHP String into array keyed by word start - php

Question

Say I have the following string
$str = "once in a great while a good-idea turns great";
What would be the best solution to creating an array with the array key being the string count of where the word(s) starts?
$str_array['0'] = "once";
$str_array['5'] = "in";
$str_array['8'] = "a";
$str_array['10'] = "great";
$str_array['16'] = "while";
$str_array['22'] = "a";
$str_array['24'] = "good-idea";
$str_array['34'] = "turns";
$str_array['40'] = "great";

Answer 1

As simple as the following:
str_word_count($str, 2);
what str_word_count() does is
str_word_count() — Return information about words used in a string

Answer 2

str_word_count() with 2 as the second argument to get the the offset; and you'd probably need to use the 3rd argument to include hyphen as well as letters in words

Answer 3

$str = "once in a great while a good-idea turns great";
print_r(str_word_count($str, 2));
demo:
http://sandbox.onlinephpfunctions.com/code/9e1afc68725c1472fc595b54c5f8a8abf4620dfc

Answer 4

Try this:
$array = preg_split("/ /",$str,-1,PREG_SPLIT_OFFSET_CAPTURE);
$str_array = Array();
foreach($array as $word) $str_array[$word[1]] = $word[0];
EDIT: Just saw Mark Baker's answer. Probably a better option than mine!

Answer 5

You can use preg_split (with the PREG_SPLIT_OFFSET_CAPTURE option) to split the string on the space, then use the offset it gives you to make a new array.
$str = "once in a great while a good-idea turns great";
$split_array = preg_split('/ /', $str, -1, PREG_SPLIT_OFFSET_CAPTURE);
$str_array = array();
foreach($split_array as $split){
$str_array[$split[1]] = $split[0];
}