replacer Introduction to the use of strtr function in PHP str_replace

strtr has two forms:
string strtr ( string $str , string $from , string $to )
string strtr ( string $str , array $replace_pairs )
When using the first type, the parameters $from, $to The length of the strings must be the same, otherwise the extra characters (whether there are more $from or more $to) characters will be ignored.
For example, $str = 'a-=b' ;
When $from='-=' ,$to= 'CD', output 'aCDb', because '-=' and 'CD' have the same length, there is no problem.
When $from='-=', $to='CDE', output 'aCDb', in $to 'E' is ignored.
When $from='-=', $to='C', 'aC=b' is output, and the '=' in $from is ignored.
When using the second form, then Without this problem, extra entries will not be ignored.
So, if you deliberately use the strtr function instead of str_replace, and use the first form, you must pay attention to this feature, which may be a trap.

The above introduces the use of strtr function in replacer and str_replace in PHP, including the content of replacer. I hope it will be helpful to friends who are interested in PHP tutorials.