Newbie Question : "grep"

[moogyd at yahoo.co.uk]

Hello,

I am attempting to write my first Python script to extract some
information from a file, and place it into another file.
(I am trying to find the physical postions of 4 cells within an FPGA)
I have a working solution, and would appreciate any comments.

for line in lines:

    if "placed" in line:
        if "i_a/i_b/ROM/" in line:
            pos = (line.split()[4]).split("_")[1]
            if "B18" in line:
               print "        i_a/i_b/ROM/B18 [7:6] LOC =", pos
            elif "B14" in line:
               print "        i_a/i_b/ROM/B14 [5:4] LOC =", pos
            elif "B10" in line:
               print "        i_a/i_b/ROM/B10 [3:2] LOC =", pos
            elif "B6" in line:
               print "        i_a/i_b/ROM/B6 [1:0] LOC =", pos
            else:
               print "Error"

Specific questions
- Use for "Phrase" in line or line.find("Phrase") >= 0 ?
- If I increase number of elements I am searching for, then I have
more elif...elif. Is there a cleaner solution?

Thanks for any feedback.

Steven