[Tutor] Omitting lines matching a list of strings from a file

[Christian Witts]

galaxywatcher at gmail.com wrote:
> I am trying to output a list of addresses that do not match a list of 
> State abbreviations. What I have so far is:
>
> def main():
>     infile = open("list.txt", "r")
>     for line in infile:
>         state = line[146:148]
>         omit_states = ['KS', 'KY', 'MA', 'ND', 'NE', 'NJ', 'PR', 'RI', 
> 'SD', 'VI', 'VT', 'WI']
>         for n in omit_states:
>             if state != n:
>                 print line
>     infile.close()
> main()
>
> This outputs multiple duplicate lines. The strange thing is that if I 
> change 'if state == n:' then I correctly output all matching lines. 
> But I don't want that. I want to output all lines that do NOT match 
> the States in the omit_states list.
>
> I am probably overlooking something very simple. Thanks in advance.
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The more pythonic way of doing it would be to use `not in` like listed 
below.  You should consider normalizing your input (state) by using 
.upper() unless you know for certain it's always upper-case.

state = line[146:148]
omit_states = ['KS', 'KY', ..., 'VT', 'WI']
if state not in omit_states:
    print line

-- 
Kind Regards,
Christian Witts
Business Intelligence

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