readline in while loop

[Geert Fannes]

hello, i tried to construct a program to read a file, line after line. i 
have no idea why it does not work...

f=file("test.txt","r");
while l=f.readline():
	print l;

the problem is with "while l=f.readline():" the next program does work

f=file("test.txt","r");
while f.readline():

i tried things like

f=file("test.txt","r");
while (l=f.readline())!="":
	print l;

but that doesn't work either. just reading the lines is not enough, i 
want to do something with the read lines.

geert.