Merge two files in Python and sort

Question

I am trying to create a function that combines 2 text files, and sorts them, before writing the result to a new file. I have read the existing threads about sorting files, as well as the threads about merging files, but I haven't been able to find one that answers my question.

File1:
12:24:00: 14, 15, 16
20:13:09: 1, 2, 3

File2:
08:06:02: 43, 54, 10
15:16:05: 6, 2, 12

And the desired output would be this:

NewFile:
20:13:09: 1, 2, 3
15:16:05: 6, 2, 12
12:24:00: 14, 15, 16
08:06:02: 43, 54, 10

I originally tried to merge the content of both files into one list, and then sort it, before writing it to a new file, but that didn't seem to work. Here is what I have tried so far:

def mergeandsort(file1, file2, NewFile):
    s1, s2, d=open(src1, 'r'), open(src2, 'r'), open(dst, 'w')
    l=[]
    l.append(list(s1))
    l.append(list(s2))
    n=sorted(l)
    c=''.join(str(n))
    d.write(c)
    s1.close(); s2.close(); d.close()

I am new to Python, so any help would be appreciated!

sorting is according to time? each row contain time and followed by 3 integer values? — Vivek Sable
– Vivek Sable, Commented Mar 23, 2016 at 4:09
Yes, I had to write a function that just sorted one file and using the "sorted" function worked to sort based on the first three values (which make up the time). — sophia
– sophia, Commented Mar 23, 2016 at 4:10

Clément Mangin · Accepted Answer · 2016-03-23 04:24:42Z

5

Trying to fix your implementation:

def mergeandsort(src1, src2, dst):
    # Use `with` statements to close file automatically
    with open(src1, 'r') as s1, open(src2, 'r') as s2, open(dst, 'w') as d:
        l = list(s1) + list(s2)
        l.sort(reverse=true)  # Since you seem to want them in reverse order...
        c = ''.join(l)
        d.write(c)

Note that this is not optimal if you manipulate big files...

answered Mar 23, 2016 at 4:24

Clément Mangin

4343 silver badges8 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Vivek Sable · Accepted Answer · 2016-03-23 04:35:48Z

4

Following are step:

Read files and then create list of there data.
Add two list
so sorted function for sorting.
Use reverse method of list
Write content into file. (you can do this)

Demo:

>>> p1 = '/home/vivek/Desktop/f1.txt' 
>>> p2 = '/home/vivek/Desktop/f2.txt' 
>>> 
>>> fp1 = open(p1)
>>> fp2 = open(p2)

>>> l1 = fp1.read().strip().split("\n")
>>> l1
['12:24:00: 14, 15, 16', '20:13:09: 1, 2, 3']
>>> l2 = fp2.read().strip().split("\n")
>>> l2
['08:06:02: 43, 54, 10', '15:16:05: 6, 2, 12']
>>> l3 = l1+ l2
>>> l3
['12:24:00: 14, 15, 16', '20:13:09: 1, 2, 3', '08:06:02: 43, 54, 10', '15:16:05: 6, 2, 12']
>>> sorted(l3)
['08:06:02: 43, 54, 10', '12:24:00: 14, 15, 16', '15:16:05: 6, 2, 12', '20:13:09: 1, 2, 3']
>>> merge_list = sorted(l3)
>>> merge_list.reverse()
>>> merge_list
['20:13:09: 1, 2, 3', '15:16:05: 6, 2, 12', '12:24:00: 14, 15, 16', '08:06:02: 43, 54, 10']
>>>

Function:

def mergeandsort(file1, file2, output):
    fp1, fp2 = open(file1, 'r'), open(file2, 'r')
    merge_data = fp1.read().strip().split("\n") + fp2.read().strip().split("\n")
    merge_data = sorted(l3, reverse=True)
    fp = open(output, 'w')
    for i in merge_data:
        fp.write(i)

    fp.close()
    return True, output


p1 = '/home/vivek/Desktop/f1.txt' 
p2 = '/home/vivek/Desktop/f2.txt' 
p3 = '/home/vivek/Desktop/f12.txt' 

print mergeandsort(p1, p2, p3)

edited Mar 23, 2016 at 4:35

answered Mar 23, 2016 at 4:18

Vivek Sable

10.3k6 gold badges45 silver badges63 bronze badges

2 Comments

sophia Over a year ago

thank you! when I write this into another file, how do I make it so that the result goes back to being formatted into lines?

Bahrom Over a year ago

Use '\n'.join(merge_list) when writing

Bahrom · Accepted Answer · 2016-03-23 04:26:12Z

2

Here's an alternative that sorts based on datetime (assuming you read the contents of f1 and f2 into two lists, l1 and l2):

l1 = ['12:24:00: 14, 15, 16', '20:13:09: 1, 2, 3']
l2 = ['08:06:02: 43, 54, 10', '15:16:05: 6, 2, 12']

from datetime import datetime

for x in sorted(l1 + l2, key=lambda time_and_nums: datetime.strptime(time_and_nums.split(' ')[0][:-1], '%H:%M:%S'), reverse=True):
    print(x)

Will print

20:13:09: 1, 2, 3
15:16:05: 6, 2, 12
12:24:00: 14, 15, 16
08:06:02: 43, 54, 10

answered Mar 23, 2016 at 4:26

Bahrom

4,87235 silver badges44 bronze badges

Collectives™ on Stack Overflow

Merge two files in Python and sort

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related