PHP Basics (Grooming)

1. The difference between GLOBAL and $global[']

　　Global $a 1; An external $ A reference or pointer to the same name.

$GLOBAL [' a ']; An external $ A reference or pointer to the same name.

2. substr () function--intercept string

　　SUBSTR () The string is truncated, the string has Chinese characters, there may be an error, you can use MB_SUBSTR (), and the Mb_substr () function is followed by a parameter that sets the encoding.

1 echo ' <br>1 '. substr ("ABCDEFG", 2, 4); 2 echo ' <br>2 '. substr ("Qin time the Moon Han time Off", 2, 4); 3 echo ' <br>3 '. mb_substr ("Qin Time Bright Moon Han time Off", 2, 4, ' UTF8 ');

PHP Basics (Grooming)