Python Loop Only Iterating once with Large loop which takes input from a file

Question

I'm doing this project and it needs to take input from names from the https://www.ssa.gov/oact/babynames/limits.html , so i created a loop to get all the names in the file and then made another to check for the largest name. However the loop only seems to run through once and gives the first name in the list. Is there a way to make it so it goes through the list?

    ## https://www.ssa.gov/oact/babynames/limits.html
file = open('yob2003.txt', 'r')
# variables to store the most popular name
# and the most popular name count
most_pop_name = ""
allNames = set()
count = 0

for line in file:  # loop to check for names
    list = line.split(',')
    if int(list[2]) > 100:  # not worth to work with stuff under 100
        allNames.add(list[0])
print(len(allNames))

bigList = sorted(allNames)

file.close()
file = open('yob2003.txt', 'r')
for x in range(len(bigList)):  # big loop that goes through once
    total = 0
    for line in file:
        list = line.split(',')
        if bigList[x] == list[0]:
            total += int(list[2])

    if total > count:
        most_pop_name = str(list[0])
        total = count

    #  print most popular name

print("Most popular name in [NJ] :: " + str(most_pop_name) + " " + str(count))

to get the yob2003 you need to downlod the national data and find the yob2003.txt — Nathaniel Carlyon
– Nathaniel Carlyon, Commented Nov 22, 2019 at 15:43
file is an iterator. After you iterated it in your first loop, it is exhausted. Open the file anew or reset it to the first position with seek(0) — tobias_k
– tobias_k, Commented Nov 22, 2019 at 15:45
Also, it might be better to use some sort of dict instead of reading the entire file again for each entry in big-file. — tobias_k
– tobias_k, Commented Nov 22, 2019 at 15:46

ashiswin · Accepted Answer · 2019-11-22 15:52:39Z

1

The issue with the loop is that you do for line in file. Every time you read a line from the file, it advances the read pointer within the file by a line. So the first time your big loop runs, it hits the inner loop and reaches the end of the file. Hence all subsequent iterations through big loop reach the inner loop, notice the file has reached the end, skips it and continues.

You are gonna want to reopen the file for each iteration of your big loop (move file = open('yob2003.txt', 'r') to after your for x in range(len(bigList)):.

Side note: Don't name your variable list as list refers to the Python data structure list(). This redefinition could cause confusions and bugs later on, so just beware.

Efficiency note: You open the file a lot and perform a lot of looping. It might be better to just execute everything in the first loop using a dictionary. For example:

import collections

file = open('yob2003.txt', 'r')
most_pop_name = ""
max_count = 0
counts = collections.defaultdict(int)

for line in file:
    arr = line.split(',')
    if int(arr[2]) < 100: continue

    counts[arr[0]] += int(arr[2])
    if counts[arr[0]] > max_count:
        max_count = counts[arr[0]]
        most_pop_name = arr[0]

# Python 2
print("Most popular name in [NJ] :: " + most_pop_name + " " + str(max_count))
# Python < 3.6
print("Most popular name in [NJ] ::", most_pop_name, max_count)
# Python >= 3.6
print(f"Most popular name in [NJ] :: {most_pop_name} {max_count}")

edited Nov 22, 2019 at 15:52

answered Nov 22, 2019 at 15:47

ashiswin

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2 Comments

Nathaniel Carlyon Over a year ago

I have having a lot of trouble and created stackoverflow account just to post this. The list is named like because the assignment was given with a template, and for grading purposes I don’t change it. I’ll use the collections for things like in the future, thank you!

ashiswin Over a year ago

Understood, glad the solution helped you though! :)

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