how to remove new lines and returns from php string?

Question

A php variable contains the following string:

text
text2

item1
item2         


        

Answer 1

You need to place the \n in double quotes.
Inside single quotes it is treated as 2 characters '\' followed by 'n'

You need:

$str = str_replace("\n", '', $str);

A better alternative is to use PHP_EOL as:

$str = str_replace(PHP_EOL, '', $str);