Question

Trying to get a list of all substrings currently I have a function but it’s not fully complete. Im using minimum char of 4. What would be a good approach to complement this:

Im also need to find words like “predict”, how can this be done best and fastest?

Output

Word:      predictions
Substring: predictions
Substring: redictions
Substring: edictions
Substring: dictions
Substring: ictions
Substring: ctions
Substring: tions
Substring: ions

Answer 1

The following will create a substring trimming from the right and left of the word down to length of 4 in the same loop. That was the specification I understood.

$length = strlen($word) - 4;
for ($i = 1; $i <= $length; ++$i) {
    echo "left = ", substr($word, $i), PHP_EOL;
    echo "right = ", substr($word, 0, -$i), PHP_EOL;
}

Assumption: By words you mean substrings.

Note: I also added the logic for a minimum length of 4 characters as well as micro-optimized the for loop (static limit and pre-increment counter).