CODEWITHSUNDEEP
pythonpython-3.xstringinteger
HeavenlyMoo
HeavenlyMoo

Reputation: 11

How to convert old list of string into new list of int

I want the strings converted into integer. tried doing it this way but for some reason it doesn't work

newList = []
myList = [['1', '2'], ['3', '4'], ['5', '6']]

for i in range (len(myList)):
    for j in i:
        
        b = int(myList[i][j])
        newList.append(b)
    
   
   
print(newList)

I want the outcome to look like this:

[[1, 2], [3, 4], [5, 6]]

Upvotes: 1

Views: 70

Answers (4)

mikuszefski
mikuszefski

Reputation: 4043

While i would use one of the solutions given by other members, here one simple one using numpy:

import numpy
myList = [['1', '2'], ['3', '4'], ['5', '6']]
newlist = numpy.array( myList, dtype=int )

Memory wise probably not the best, but quite good readability. Though, at the end it is not a list, but a numpy array.

Upvotes: 0

Sanchit.Jain
Sanchit.Jain

Reputation: 608

you can also use map:

newList = [list(map(int, i)) for i in myList]

Actually, for this type of problem list comprehension and map are somewhat interchangeable and the answer uses both.

Upvotes: 1

taebeom shin
taebeom shin

Reputation: 21

Answer above is very good, but I'd like to make code with your intention

newList = []
myList = [['1', '2'], ['3', '4'], ['5', '6']]

for i in range(len(myList)):
    tempList=[]#we need tempList to make element list
    #for j in i -> this makes error because for loop cant use in integer without range()
    for j in range(len(myList[i])):
        b = int(myList[i][j])
        tempList.append(b)#make element list
    newList.append(tempList)#append element list to newlist

print(newList)

I wish this can help you. Thanks :)

Upvotes: 2

Alexander Riedel
Alexander Riedel

Reputation: 1359

thats the way:

myList = [['1', '2'], ['3', '4'], ['5', '6']]
new_list = [[int(i) for i in e] for e in myList]

with for i in range(len(myList)): you iterate through the index of the list, and not the elements itself. What you wanted to do:

newList = []
myList = [['1', '2'], ['3', '4'], ['5', '6']]

for i in myList:
    stack = []
    for j in i:
        stack.append(int(j))
    newList.append(stack)

print(newList)

Upvotes: 2

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