[Tutor] make code less ugly/more pythonic?

[Daniel Ehrenberg]

ashleigh smythe wrote:
> Greetings!  I've written a little script to process
> a text file.  It
> does exactly what I want it to do but as I'm a
> newbie I'm sure it's very
> ugly and brute force - I wondered if anyone had a
> moment to please take
> a look and tell me how to improve it?  For instance
> I have a function
> that calls a function that calls a function!  Is
> that awkard and
> unpythonic?  Should the whole thing be in a class -
> how would I do that?
> 
> The program simply parses a file that has 10,000
> iterations of the
> following:
> 
> 
> Strict consensus of 1 tree:
> 
> Statistics derived from consensus tree:
> 
>      Component information (consensus fork) = 185
> (normalized = 0.964)
>      Nelson-Platnick term information = 3855
>      Nelson-Platnick total information = 4040
>      Mickevich's consensus information = 0.183
>      Colless weighted consensus fork (proportion
> max. information) =
> 0.216
>      Schuh-Farris levels sum = 0 (normalized =
> 0.000)
>      Rohlf's CI(1) = 0.989
>      Rohlf's -ln CI(2) = 948.111 (CI(2) = 0.00)
> 
> 
> I want to extract that Component information
> (consensus fork) value (185
> in this instance) from each of the 10,000
> "paragraphs" of data in the
> file and get an average of that value.
> 
> 
> Below is the code I hacked together- please don't
> laugh!!!  :-)
> 
> Thanks for any imput,
> 
> Ashleigh
> 
> import re
> import sys
> import string
> 
> def make_int(mylist):                     #turns the
> list of consensus 
>     an_int_list=[int(n) for n in mylist]  #fork
> values from strings to
>     return an_int_list                    #integers
> so I can average
>                                           #them.
> def add_up(mylist):                       #calls
> function to turn
>     int_list=make_int(mylist)             #strings
> into          
>     asum=0                                #integers.
>     for x in int_list:                    #sums up
> all the values
>         asum +=x
>     return asum
> 
> def average(mylist):                      #takes the
> sum of consensus
>     sum=add_up(mylist)                    #fork
> values and finds their  
>     length=len(mylist)                    #average.
>     average_confork=sum/length
>     return average_confork
> 
> mainlist=[]                              
> #initialize the list of 
>                                           #consensus
> fork values.
> def search(file_to_search):               
>     infile=open(file_to_search, 'r')
>     for line in infile:
>         if re.search('Component', line):  #searches
> the input file for
>             confork=line[45:49]           #line
> containing cons. fork,
>             mainlist.append(confork)      #removes
> the value and puts 
>     return mainlist                       #it into a
> list.
> 
> def aveconfork(file_to_search):           #this
> executes the whole thing
>     thelist=search(file_to_search)        #so I
> start the program with 
>     finalaverage=average(mainlist)       
> #aveconfork.aveconfork
>     return finalaverage                  
> #('file_to_search')

Your program is good. It does what it is supposed to
do. I do have a few changes to it, though. Here's my
edited version:

def avg_str_list(L):
    newlist = [int(x) for x in L]
    return sum(newlist) #sum adds up everything in
list

def find_comp_if_there(string):
    if string.startswith('Component'):
        return string[45:49]

def go_through_file(filename):
    thisfile = file(filename) #mode 'r' implied
    mainlist = []
    for line in thisfile:
        cur_comp = find_comp_if_there(line)
        if cur_comp: mainlist.append(cur_comp)
    return mainlist

This uses the same underlying algorithm as your
program does.

Daniel Ehrenberg

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