substr_count not working with new lines?

问题

This is driving me nuts, it keeps returning 0

substr_count('df
d
fd
f
df', '\n');

if I use a letter like "d", it works fine

substr_count('df
d
fd
f
df', 'd');

Can anyone shed some light on this?

Thanks

回答1:

You need to use double quotes for control characters:

var_dump(substr_count('df
d
fd
f
df', "\n"));

回答2:

'\n' is not the same as "\n". '\n' is text comprising a slash and the letter "n", whereas "\n" is a newline character.

Suggest you read the relevant section of the PHP manual about strings, particularly where it talks about single and double quoted strings.

回答3:

In addition to Alix and Mark: please use PHP_EOL instead of \n. Newlines differ on the different platforms (Windows/Linux/Mac), but PHP_EOL is always right. See this question for more info on the subject: When do I use the PHP constant "PHP_EOL"?

来源：https://stackoverflow.com/questions/10367971/substr-count-not-working-with-new-lines