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!

Answer 1

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...

Answer 2

Following are step:

1. Read files and then create list of there data.
2. Add two list
3. so sorted function for sorting.
4. Use reverse method of list
5. 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)