Equivalent string.find method for a list of strings

[jeremit0]

I have read a text file using the command

lines = myfile.readlines()

and now I want to seach those lines for a particular string.  I was 
hoping there was a way to "find" that string in a similar way as 
searching simply a simple string.  I want to do something like

lines.find.('my particular string')

Is there a module that already exists that allows me to do this or will 
I have to created my own method?
Thanks,
Jeremy