How to find non-repeating characters in a string by php

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1. Strlen () returns the length of the string.

The return value is the length of the string if successful, and 0 if the string is empty.

2. Substr_count () is used to calculate the number of times the substring appears in the string.

The return value is the number of times the substring appears in the string.

3. The substr () function is used to return part of the string.

The return value is the extracted part of the returned string, or FALSE if it fails, or an empty string.

For non-repeating characters, there should be no need to explain too much, such as the string "adicvdda". The first non-repeating character visible to the naked eye is I, because the characters an and d are repeated.

Next we will show you how to achieve this operation through PHP.

Function find_non_repeat ($word) {$chr = null; for ($I = 0; $I