Php trim space trim is invalid implement with str_replace

I usually think about spaces. I usually use trim. Today, I found that spaces in the middle cannot be removed. however, we can only find out the description. trim can only go to two ends, for example, $ abc = a B c;. trim can only remove spaces behind c in front of, but what should I do with spaces before and after B. str_replace is available.

The code is as follows:	Copy code
Str_replace ('','', $ abc ).

Please be careful when spaces are needed. php does not use spaces. trim does not work. The str_replace line is complete. However, trim can delete the header space as follows:

Example

The code is as follows:	Copy code
<? Php Trim removes spaces at both ends of a string, Rtrim removes the right space of a string, Ltrim removes the left space of a string. Echo trim ("space www.111cn.net"). "<br> "; Echo rtrim ("space"). "<br> "; Echo ltrim ("space"). "<br> "; ?>

The result is the same as that of str_replace.