CODEWITHSUNDEEP
pythonpandasnumpyfor-loop
manas
manas

Reputation: 471

Adding data to a column and append it

I have a input data in a file input.txt. I want to add 200 with each row of 4th column and want to append just beside to it in the format same as original.

Input.txt

>   >   >
0.000   5.064   -0.15835E-01 -7.755619582136471027e-03
0.700   9.064   -0.21715E-02 -1.302134466433525067e-02
0.800   5.064   0.18954E-01 -1.691809184964498253e-02
>   >   >
0.500   4.977   0.32899E-02 1.439701445411046415e-02
0.200   6.977   0.15972E-01 6.094966468334198084e-03
0.700   4.977   0.30631E-01 -5.640445453166963163e-03

out.txt

>   >   >
0.000   5.064   -0.15835E-01 -7.755619582136471027e-03 199.99224438041787
0.700   9.064   -0.21715E-02 -1.302134466433525067e-02 199.98697865533566
0.800   5.064   0.18954E-01 -1.691809184964498253e-02  199.98308190815035
>   >   >
0.500   4.977   0.32899E-02 1.439701445411046415e-02   200.01439701445412
0.200   6.977   0.15972E-01 6.094966468334198084e-03   200.00609496646834
0.700   4.977   0.30631E-01 -5.640445453166963163e-03  199.99435955454683

I tried :

import numpy as np
data=np.loadtxt('input.txt')
data1=data(:,3)+200

I am getting error ValueError: could not convert string to float: '>' I hope some expert will help me overcoming this problem.

Upvotes: 0

Views: 279

Answers (3)

sdpshaw
sdpshaw

Reputation: 46

We can achieve this without creating a new file and do the operation inplace using fileinput library. In the blow code it is preserving this ">" character too.

import sys
import fileinput

file = fileinput.input('test.txt', inplace=1)

for i, line in enumerate(file):
    if line.startswith('>'):
        sys.stdout.write(line)
    else:
        string = line.split()
        string.append('200\n')
        line = ' '.join(string)
        sys.stdout.write(line)
file.close()

output of above code:

>   >   >
0.700 4.977 0.30631E-01 -5.640445453166963163e-03 200
0.700 4.977 0.30631E-01 -5.640445453166963163e-03 200
0.700 4.977 0.30631E-01 -5.640445453166963163e-03 200
>   >   >
0.700 4.977 0.30631E-01 -5.640445453166963163e-03 200
0.700 4.977 0.30631E-01 -5.640445453166963163e-03 200
0.700 4.977 0.30631E-01 -5.640445453166963163e-03 200

Upvotes: 0

DYZ
DYZ

Reputation: 57033

You have non-numeric symbols in the file. You can treat them as comments:

data = np.loadtxt('input.txt', comments=">")

But then you will not be able to preserve them in the output file. I am afraid your only option is to read the file line by line in a loop:

CHANGE = 200
with open('input.txt') as infile, open('out.txt', 'w') as outfile:
    for line in infile:
        if not line.startswith('>'): # Needs a modification
            parts = line.split()
            parts.append(str(float(parts[3]) + CHANGE) + '\n')
            line = ' '.join(parts)
        outfile.write(line)

Upvotes: 1

FatPancake52
FatPancake52

Reputation: 66

I dont quite understand the question but I think I know what the problem is. There are a couple ways I may be able to help you:

  • Remove the >s at the beginning of the file.
  • Skip over the >s. Like this:
with open("input.txt", "r") as f:
    with open("temporaryfile.txt", "w") as temp:
        temp.write(f.read().replace(">   >   >",""))
    
    
data=np.loadtxt("temporaryfile.txt")
data1=data(:,3)+200

and just use import os;os.remove("temporaryfile.txt") to remove temporaryfile.txt afterward.

The problem is its running into those >s and that is what is causing the error. So, if you remove those, that should fix your problem.

Upvotes: 0

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