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This article mainly introduces the weird phenomena in the use ofPHP functionrtrim(), and analyzes the problems that occur in the character matching process of PHP function rtrim based on specific examples. and solutions will help to further understand the principles and usage techniques of the rtrim function. Friends in need can refer to
. This article describes the weird phenomena in the use of the PHP function rtrim(). Share it with everyone for your reference, the details are as follows:
I encountered a strange problem when using thertrim()
function today:
echo rtrim('', ''); // 输出为
The above output result is a bit unexpected, Originally, I thought the first line should output e388a4556c0f65e1904146cc1a846bee, and the second line would output jb51.net.
This problem has troubled me for a long time, and I have never found the reason. Later I found the answer in the manual:
rtrim() replaces characters in units, notString. When replacing from right to left, the 6 characters of 94b3e26ee717c64999d7867364b1b4a3 will definitely be replaced. When going to the left, > is encountered, because > is also included in the string of the second parameter of rtirm() (6fb279ad3fd4344cbdd93aac6ad173ac), so it is also replaced. When p is encountered when going to the left, p is not included in the string of the second parameter. So the substitution stops and
If you understand it this way, the output result of the second line is expected. Haha...it's clearly written in the manual. Original text:
You can also specify the characters you want to strip, by means of the charlist parameter. Simply list all characters that you want to be stripped. With .. you can specify arangeof characters.
It can be seen that the second parameter of
rtrim
,ltrim
andtrim
is used as a set of character lists for matching operations. . This is different from the replacement operation of thestr_replace
function we have known before.The above is the detailed content of Some abnormal phenomena during the use of php rtrim() function. For more information, please follow other related articles on the PHP Chinese website!