extract data from file with python

Question

I need to extract data from lines of a text file. The data is name and scoring information formatted like this:

Feature_Locations:
   - { x:9.0745818614959717e-01, y:2.8846755623817444e-01,
       z:3.5268107056617737e-01 }
   - { x:1.1413983106613159e+00, y:2.7305576205253601e-01,
       z:4.4357028603553772e-01 }
   - { x:1.7582545280456543e+00, y:2.2776308655738831e-01,
       z:6.6982054710388184e-01 }
   - { x:9.6545284986495972e-01, y:2.8368893265724182e-01,
       z:3.6416915059089661e-01 }
   - { x:1.2183872461318970e+00, y:2.7094465494155884e-01,
       z:4.5954680442810059e-01 }

This file is generated by another software. Basically I want to get that data back in this program and i want to save them in different other files for examples "axeX.txt" "axeY.txt" "axeZ.txt"

I have try this

import numpy as np
import matplotlib.pyplot as plt
import re
file = open('data.txt', "r")
for r in file:
    y = re.sub("- {", "",r).split()
    tt = y[:2]
    zz = tt
    st = re.findall('\d+', r)
    print st
file.close()

Is there a better way or I am doing it wrong ?

Sandeep · Accepted Answer · 2016-03-22 10:51:41Z

1

The input file is in YAML format. It is recommended to use PyYAML package for parsing yaml files.

import yaml

document = """
Feature_Locations:
   - { x: 9.0745818614959717e-01, y: 2.8846755623817444e-01,
       z: 3.5268107056617737e-01 }
   - { x: 1.1413983106613159e+00, y: 2.7305576205253601e-01,
       z: 4.4357028603553772e-01 }
   - { x: 1.7582545280456543e+00, y: 2.2776308655738831e-01,
       z: 6.6982054710388184e-01 }
   - { x: 9.6545284986495972e-01, y: 2.8368893265724182e-01,
       z: 3.6416915059089661e-01 }
   - { x: 1.2183872461318970e+00, y: 2.7094465494155884e-01,
       z: 4.5954680442810059e-01 }
"""

locations = yaml.load(document)['Feature_Locations']

for ch in 'XYZ':
    fname = 'axe%s.txt' %ch
    with open(fname, 'w') as fh:
        for item in locations:
            fh.write('%s\n' % item[ch.lower()])

The input file is slightly corrupted. yamllint will do a sanity check and inform us of the errors.

yamllint inputfile.yaml
inputfile.yaml
  1:1       warning  missing document start "---"  (document-start)
  2:9       error    syntax error: found unexpected ':'

In this case we can fix the input file easily.

 sed -i 's/:/: /g' inputfile.yaml

edited Mar 22, 2016 at 10:51

answered Mar 22, 2016 at 1:42

Sandeep

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1 Comment

Gustavo Bezerra Over a year ago

It seems you had to preprocess the document by adding spaces between the variables (x, y, z) and the actual values. Is there any straightforward way of doing that using PyYAML?

Gustavo Bezerra · Accepted Answer · 2016-03-22 01:40:24Z

0

You can try something like:

s = open('data.txt', "r").read()

x = re.findall(r'x:(.*), ', s)
y = re.findall(r'y:(.*),', s)
z = re.findall(r'z:(.*) ', s)

with open('axeX.txt', 'w') as f: f.write('\n'.join(x))
with open('axeY.txt', 'w') as f: f.write('\n'.join(y))
with open('axeZ.txt', 'w') as f: f.write('\n'.join(z))

answered Mar 22, 2016 at 1:40

Gustavo Bezerra

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1 Comment

ahmed Over a year ago

Work fine ! Thank you so much ! :D

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