CODEWITHSUNDEEP
python
Chang Woon Jang
Chang Woon Jang

Reputation: 125

Modifying text file using reference value

I have the following reference data like

21   1
32   2
45   3

and there is a text file (file.txt) contains two or more columns like

21  32  45
45  21  32
32  45  21

I would like to change file.txt using reference value like

1   2   3
3   1   2
2   3   1

As you can see the reference file, 21, 32, and 45 equal and match the number 1, 2, and 3, respectively.

I coded based on two for loops and compared two values. 

with open('ref') as f1, open('file.txt') as f2, open('out.txt', 'w') as f3:

     for lines in f1:
         value1 = lines.split()

         for line in f2:
             if value2 == value1[0]:
                value2 = value1[1]
                line = ' '.join(value2) + '\n'
             f3.write(line)

Nothing has been changed. How could this make it possible?

Upvotes: 0

Views: 145

Answers (3)

damienfrancois
damienfrancois

Reputation: 59260

You need a third loop to iterate over the columns of file.txt. Something like 

for line in f2:
    value2 = line.split()
    for item in value2:
        if item == value1[0]:
            value2 = value1[1]

A dict seems a good fit to your problem:

#/usr/bin/env python
ref = {}
with open("ref") as file:
    for line in file:
        k, v = line.split()
        ref[k] = v

with open("file.txt") as file, open("res", 'w') as res:
        for line in file:
            for item in line.split():
                res.write("%s\t" % ref[item])
            res.write("\n")

Upvotes: 1

Farhadix
Farhadix

Reputation: 1457

mydict = {}
with open('ref') as f1:
    for line in f1:
        key, value = line.split()
        mydict[key] = value

with open('file.txt') as f2, open('out.txt', 'w') as f3:
    for l in f2:
        line = l.split()
        newline = ''
        for item in line:
            newline += mydict[item] + " "
        f3.write(newline + "\n")

Upvotes: 1

JoeC
JoeC

Reputation: 1850

You are NOT comparing it right

with open('ref') as f1, open('file.txt') as f2, open('out.txt', 'w') as f3:

 for lines in f1:
     value1 = lines.split()

     for line in f2:
         value2 = line.split() # value2 is a list
         if value2 == value1[0]: # if a list is equals to a value => always false
            value2 = value1[1]
            line = ' '.join(value2) + '\n'
         f3.write(line) # so line is still the original line since the if statement is always false

Upvotes: 1

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