CODEWITHSUNDEEP
pythonlist
TheArmaniCode
TheArmaniCode

Reputation: 29

Comparing list values and storing new ones in a separate list

import csv

with open("DADSA RESIT CWK JULY 2018.csv", newline='') as f:
    r = csv.reader(f)
    database = list(r)

del database[0]
names = []
names.append([])

def fillnames(d, n):
    for j in n:
        for i in d:
            if d[i][0] == n[j][0] and d[i][1] == n[j][1]:
                n[i][2] = n[i][2]+1
            else:
                names.append([d[i][0], d[i][1], 0])

fillnames(database, names)

for i in names:
    print(i)

The code I have here is me scanning in a csv file into a list. I then want to count how many entries share the same name, by scanning each new name into a separate list, then incrementing the number found every time I find a new one. Every time I run this code it returns "TypeError: list indices must be integers or slices, not list."

Upvotes: 0

Views: 43

Answers (1)

Steven Rumbalski
Steven Rumbalski

Reputation: 45542

If you don't need database:

import csv
from collections import Counter

with open("DADSA RESIT CWK JULY 2018.csv", newline='') as f:
    reader = csv.reader(f)
    next(reader) # discard headers
    name_counts = Counter((row[0], row[1]) for row in reader)

If you do need database:

import csv
from collections import Counter

with open("DADSA RESIT CWK JULY 2018.csv", newline='') as f:
    reader = csv.reader(f)
    next(reader) # discard headers
    database = list(reader)
name_counts = Counter((row[0], row[1]) for row in database)

The root error in your original code is this:

for i in d:
    if d[i] ...

When you do for item in somelist in Python item is not an index, it's the actual item. In the case of for i in d, d is a list of lists--so i is one of the sublists (one of the rows). You should now see why Python would be confused by d[i] and give "TypeError: list indices must be integers or slices, not list."

Upvotes: 2

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