How to split two columns in a table in python

Question

There is table of data

now I need to split data in the two columns and merge them in to a single list The code I have written below does the job for single digit numbers but not for two or three digit numbers.

myfile = open("karate.txt","r") #read and write to a file 

for line in myfile.read():   # read data in the file
    fields = ' '.join(line.split()) # split columns of table based on space   
    print fields
    rows = map(int,fields) # converting tuple to integer
    data.extend(rows)

The output of this code for the above data is

but I need the output as

Have you tried to load the file with `np.loadtxt`. Then the data is loaded as a matrix which I think is more easy to handle. — Daniel Thaagaard Andreasen, Feb 18 '14 at 00:18
I know that numpy would be more easier but my professor has not allowed us to use numpy constructs so it has to be more naive approach... but thanks for the reply... — user2014111, Feb 18 '14 at 00:24

score 2 · Answer 1 · edited May 23 '17 at 12:29

The problem can essentially be divided into two stages: Read in the numbers as a list containing lists, then flatten the list.

fields = []
with open("text.txt") as f:
    fields = [line.split(' ') for line in f]

print fields
# [(1, 2), (1, 3), (33, 34), (10, 22), ...etc... ]

flattened = [i for tup in fields for i in tup]
print flattened
# [1, 2, 1, 3, 33, 34, 10, 22, 11, 23, ...etc...]

# Print line by line:
print '\n'.join(flattened)

This should print out the output that you're looking for.

lightalchemist · Answer 2 · 2014-02-18T04:00:42.067

# Method 1
fields = []
with open("testfile.txt") as infile:
    for line in infile:
        fields.extend(line.split())  # Note that the elements are "strings".

print("-" * 50)
print(fields)
print("-" * 50)
print("On separate lines")
print('\n'.join(fields))
print("-" * 50)
print("With lines in between")
print("\n\n".join(fields))
print("-" * 50)

# Method 2
fields = []
with open("testfile.txt") as infile:
    map(lambda line: fields.extend(line.split()), infile)

print("A slightly shorter implementation")
print(fields)
print("-" * 50)

Output:

--------------------------------------------------
['1', '2', '1', '3', '33', '34', '10', '22', '11', '23', '25', '26', '27', '28']
--------------------------------------------------
On separate lines
1
2
1
3
33
34
10
22
11
23
25
26
27
28
--------------------------------------------------
With lines in between
1

2

1

3

33

34

10

22

11

23

25

26

27

28
--------------------------------------------------
A slightly shorter implementation
['1', '2', '1', '3', '33', '34', '10', '22', '11', '23', '25', '26', '27', '28']
--------------------------------------------------

How to split two columns in a table in python

2 Answers2