How to read variating data into dictionary?

How to read variating data into dictionary?

I need to extract the name of the constants and their corresponding values from a .txt file into a dictionary. Where key = NameOfConstants and Value=float.

The start of the file looks like this:

speed of light             299792458.0        m/s  gravitational constant     6.67259e-11        m**3/kg/s**2  Planck constant            6.6260755e-34      J*s  elementary charge          1.60217733e-19     C     

How do I get the name of the constants easy?

This is my attempt:

with open('constants.txt', 'r') as infile:      file1 = infile.readlines()      constants = {i.split()[0]: i.split()[1] for i in file1[2:]}  

I'm not getting it right with the split(), and I need a little correction!

Answer by Joern Boegeholz for How to read variating data into dictionary?

Have You tried using regular expressions? for example

([a-z]|\s)*  

matches the first part of a line until the digits of the constants begin.

Python provides a very good tutorial on regular expressions (regex) https://docs.python.org/2/howto/regex.html

You can try out your regex online as well https://regex101.com/

Answer by Juraj Bezruka for How to read variating data into dictionary?

{' '.join(line.split()[:-2]):' '.join(line.split()[-2:]) for line in lines}  

Answer by SIslam for How to read variating data into dictionary?

What about re.split-

import re  lines = open(r"C:\txt.txt",'r').readlines()  for line in lines:      data = re.split(r'\s{3,}',line)      print "{0}  :  {1}".format(data[0],''.join(data[1:]))  

Or use oneliner to make dictionary-

{k:v.strip() for k,v in [(re.split(r'\s{3,}',line)[0],''.join(re.split(r'\s{3,}',line)[1:])) for line in open(r"C:\txt.txt",'r').readlines() ]}  

Output-

gravitational constant  :  6.67259e-11m**3/kg/s**2    Planck constant  :  6.6260755e-34J*s    elementary charge  :  1.60217733e-19C  

Dictionary-

{'Planck constant': '6.6260755e-34J*s', 'elementary charge': '1.60217733e-19C', 'speed of light': '299792458.0m/s', 'gravitational constant': '6.67259e-11m**3/kg/s**2'}  

Answer by AnkurJatt for How to read variating data into dictionary?

From your text file I'm unable to get the correct value of no of spaces to split. So below code is designed to help you. Please have a look, it worked for you above stated file.

import string  valid_char = string.ascii_letters + ' '  valid_numbers = string.digits + '.'    constants = {}  with open('constants.txt') as file1:      for line in file1.readlines():          key = ''          for index, char in enumerate(line):              if char in valid_char:                  key += char              else:                  key = key.strip()                  break          value = ''            for char in line[index:]:              if char in valid_numbers:                  value += char              else:                  break            constants[key] = float(value)    print constants  

Answer by Thomas for How to read variating data into dictionary?

with open('constants.txt', 'r') as infile:      lines = infile.readlines()      constants = {' '.join(line.split()[:-2]):float(' '.join(line.split()[-2:-1])) for line in lines[2:]}  

Since there were two lines above not needed.

Answer by Ytsen de Boer for How to read variating data into dictionary?

This would best be solved using a regexp.

Focussing on your question (how to get the names) and your desires (have something shorter):

import re    # Regular expression fetches all characters  # until the first occurence of a number  REGEXP = re.compile('^([a-zA-Z\s]+)\d.*$')    with open('tst.txt', 'r') as f:        for line in f:            match = REGEXP.match(line)            if match:                # On a match the part between parentheses              # are copied to the first group              name = match.group(1).strip()            else:                # Raise something, or change regexp :)              pass  

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