Change a value with configparser for python

by BjkPosted on July 10, 2019 Posted in Python, Uncategorized

configparser is a great module to store configuration information into a file
https://docs.python.org/2/library/configparser.html
a config file could look like this:

[DEFAULT]
value = 7

To load the value from the file

import configparser

config = configparser.ConfigParser()
config.read('config.ini')
value = self.config['DEFAULT']['value']
print(value)
# output value 7

To change the value in the file:

# set new value
config.set('DEFAULT', 'value', '42')

# save the file
with open(self.config_filename, 'w') as configfile:
    config.write('config.ini')

Dictionary changed size during iteration while using pop() in python

by BjkPosted on July 9, 2019 Posted in Python, Uncategorized

Running through a json file remove all keys but one

for key in obj.keys():
        if key != 'multiverseId':
                print(key)
                obj.pop(key)

This is fine running python2 but in python3 you will run into this error

Calling keys() in python2 makes a copy of the keys that we iterate through. This is not how it works in python3, this returns an iterator instead of a list, hence the error we get while we try to run through the list and deleting keys. What we can do is converting in into a list

for key in list(obj.keys()):
        if key != 'multiverseId':
                obj.pop(key)
                print(key)

Remove non letter characters before and after characters in Python

by BjkPosted on July 8, 2019 Posted in Python, Uncategorized

To remove none letters characters from the beginning and end in python use regex from the re.py library. I needed it to remove spaces as well but not in between the words.

Here’s what I did:

import re

s = '( $My letters]'
s = re.sub('^[^a-zA-z]*|[^a-zA-Z]*$','',s)

print(s)

Output:

My letters