[Tutor] Finding text in a long string

[Timothy M. Brauch]

I am just having troubles with something I know is easy.

I've got a small script written that pulls the data from a webpage.  What I
am trying to do is to see if "image1.gif" is in the html or not.  The
problem I am having is that it might be labelled as
http://domain.com/image1.gif or it might be ../images/image1.gif or
something else (it can change with each page) and it is going to be in an
html tag.  I could do it if "image1.gif" was plain text.  I'm having trouble
however in this case.

I tried some things like:

data = urllib.urlopen(ADDRESS).read()
if "image1.gif" in data:
    print "Success"
else: print "Failure

That gives me the error
Traceback (most recent call last):
  File "<pyshell#23>", line 1, in ?
    if "offline.gif" in data:
TypeError: 'in <string>' requires character as left operand
which tells me it can only check if a certain character is in a string or
not.

I've tried

dataList = data.split()
for i in dataList:
    if "image1.gif" in i
    ...

I get the same error.  I've tried.  Because the location of "image1.gif" can
change and it could be either a relative location or an absolute location,
the following doesn't work either:

for i in dataList:
    if i == "image1.gif"

I feel like a regular expression would help here, but I'm not sure how I
would do this.  Any suggestions?

 - Tim