I have a php file that processes a csv file downloading images and replaces a url in it. I am trying to add some code to replace SUV with 123 at the first instance in each row. I have this:

for($i=1;$i<$datalen;$i++)

{

echo str_replace('SUV','123',$i,'1');

...and I'm getting this error:
Fatal error: Only variables can be passed by reference in ... on line 38

All I did to the original functional code was add the line: echo str_replace('SUV','123',$i,'1');

Any help is appreciated.

I don't understand, why you are putting the variable $i? its an integer.
you have to put the String variable you want to replace the text.
some thing like echo str_replace('SUV','123',$data[$i]);
post some more code for help