Import data into Python from txt file

Question

I have a .txt file with data arranged as follows:

3430 4735 1
3430 4736 1
3430 4941 2
3430 5072 1
3430 5095 1
3430 5230 1
3430 5299 1
3430 5386 1
3430 5552 1
3430 5555 1
3430 5808 1
3430 5853 1
3430 5896 1
3430 5988 1
3430 6190 4
3430 6191 1
3430 6225 1
3430 6296 1

How can I create Python lists from this, one containing the numbers from the first column, and the other containing the numbers from the second column?

Jérémy Caré · Accepted Answer · 2017-05-02T13:43:36.367

1

Take a look on pandas library, it's very useful for data flow. http://pandas.pydata.org/

Or you can do this directly :

list1 = []
list2 = []
list3 = []
with open('test.txt', 'r') as f:
    content = f.readlines()
    for x in content:
        row = x.split()
        list1.append(int(row[0]))
        list2.append(int(row[1]))
        list3.append(int(row[2]))

edited May 02 '17 at 13:43

answered May 02 '17 at 13:35

Jérémy Caré

315
3
12

This also gives me the error "IndexError: list index out of range". What am I doing wrong? – user8321044 May 02 '17 at 14:10
With the example file ? – Jérémy Caré May 02 '17 at 14:16
1

Add a length check before accessing & updating the list inside the for loop. – nazia May 02 '17 at 14:22
The resulting lists have strings as elements. How do I make it so that I have integers instead? @JérémyCaré – user8321044 May 02 '17 at 15:30
In my code i cast all elements to int, so they are integers not string. Take a look on int() function – Jérémy Caré May 03 '17 at 07:19

score 0 · Answer 2 · answered May 02 '17 at 13:42

0

one_list = []
another_list = []
with open("somefile.txt", "r") as this_file:
    for line in this_file:
        one_list.append(line.split(' ')[0])
        another_list.append(line.split(' ')[1])

Puts the first elements from each line in the file into one list and all the second elements into another list.

answered May 02 '17 at 13:42

TLOwater

638
3
13

Thanks. When I try to run it, I get the following error: "IndexError: list index out of range" – user8321044 May 02 '17 at 14:08

trotta · Answer 3 · 2017-05-03T13:36:37.137

0

Something like this?

flst = []
slst = []
tlst = []

file = open('your.txt', 'r')
for line in file:
    a = line.split()
    flst.append(int(a[0]))
    slst.append(int(a[1]))
    tlst.append(int(a[2]))

Create three empty lists, open the file and read through every line of the txt-file. Then split the lines and add in every line the first, second and third string to a respective list.

edited May 03 '17 at 13:36

answered May 02 '17 at 13:43

trotta

1,232
1
16
23

The list elements turn out to be strings while I would prefer them to be integers. How can I fix that? – user8321044 May 02 '17 at 15:24
You can turn them into integers. I changed the example code. – trotta May 03 '17 at 13:37

score 0 · Answer 4 · answered May 02 '17 at 14:01

0

list1 = []

list2 = []
whith open('a.txt','r') as fh:
  lineList = fh.readlines()
  for line in listList:
    numbers = line.strip().split()
    list1.appned(numbers[0])
    list2.extend(numbers[1:])

print(list1)
print(list2)

answered May 02 '17 at 14:01

Fuji Komalan

1,979
16
25

Import data into Python from txt file

4 Answers4