在python中，将文件读入2D列表后，使用函数，我应该怎么做，不要让2D列表为空

Question

I read in a text file, with a format: ola,2 ola,4 ola,6

And i read this file in using the reading function that removes all the spare elements in the list:

import csv

def read(name,practicef):
    temp=[]
    name=name+".txt"
    practicef = list(csv.reader(open(name,"r")))
    print(practicef)
    print(len(practicef))
    temp=practicef
    practicef=[]
    for item in temp:
        if item!=[]:
            practicef.append(item)
            print(practicef)
    return practicef

And then when I wanted to compare the elemnts in the list to my password, the list was empty, I am just wondering why it did this and how i could avoid it. The whole code together as it comes in the sequence is:

import csv

def read(name,practicef):
    temp=[]
    name=name+".txt"
    practicef = list(csv.reader(open(name,"r")))
    print(practicef)
    print(len(practicef))
    temp=practicef
    practicef=[]
    for item in temp:
        if item!=[]:
            practicef.append(item)
            print(practicef)
    return practicef



practicef=()
name="lollington"
read(name,practicef)
use=input("use")
pw=input("pw")
print(len(practicef))

for i in range(0,len(practicef)):
    print(use,pw)
    print(practicef[i][0],practicef[i][1])
    if use== practicef[i][0] and pw == practicef[i][1]:
        print("successful login")

Answer 1

it's a bit hard to follow what you want to do, however you actually don't use the results of your function.

does

practicef = read(name,practicef)

get you closer to where you want to be?

here is my output after that change (added a bit extra on the prints so it's easier to see where they are from):

in read [['ola', '2 ola', '4 ola', '6']]
len in read 1
[['ola', '2 ola', '4 ola', '6']]

use: ola

pw: 2
outer list len after fcn call: 1
uid ola pw 2
ola 2 ola