php str_replace single quotation marks double quotation marks difference

php str_replace () function of the specific situation

str_replace ($ search, $ replace, $ subject)

E.g

1

str_replace ("n", "
", '465s4d6f5s4ad1as65d4fa6sn54df65sdafgsdfn65g4sd65g4hdf6n54ghd6fbghdfgh'); // Note the quotes

Output: 465s4d6f5s4ad1as65d4fa6sn54df65sdafgsdfn65g4sd65g4hdf6n54ghd6fbghdfgh

2

str_replace ("n", "
"," 465s4d6f5s4ad1as65d4fa6sn54df65sdafgsdfn65g4sd65g4hdf6n54ghd6fbghdfgh "); // Note the quotes

Output:

465s4d6f5s4ad1as65d4fa6s

54df65sdafgsdf

65g4sd65g4hdf6

54ghd6fbghdfgh

3

str_replace ('n', '
', "465s4d6f5s4ad1as65d4fa6sn54df65sdafgsdfn65g4sd65g4hdf6n54ghd6fbghdfgh"); // Note the quotes

Output:

465s4d6f5s4ad1as65d4fa6s 54df65sdafgsdf 65g4sd65g4hdf6 54ghd6fbghdfgh

Note: Single quotes simply represent pure strings

The double quotes are to be compiled by the compiler

In other words, 'n' and 'n' are different, the former refers to the string n, which is the compiler n, is the meaning of the transfer character

So when only the $ search and $ subject variables are single or double quotes at the same time will have an effect.

From the text box or take out the value is transferred, that is to say there is a transfer of n, so use 'n' is useless, be sure to use "n"