Python Syntax.md

Data Types

Dumping complex structures

import json
print json.dumps(something)

Python Arrays (Lists)

Print array of strings:

print "\n".join(arr)

Iterating by index

for i in range(len(arr)):
  print arr[i]

Exceptions

try:
   # Do something
except Exception as e:
   print(e)

For empty exception clauses add the pass statement.

Standard Tasks

Passing CLI arguments

import sys

print(sys.argv[0])      # Access C-like argv array as needed

Using env variables

import os
print(os.environ)

print(os.environ.get('HTTPS_PROXY'))
os.environ['MYVAR'] = 'myvalue'

Reading lines from file

with open("myfile.txt") as f:
    content = f.read().splitlines()

Reading from a Pipe in Python

Line by line

proc = subprocess.Popen(['/bin/ls', 'something'],stdout=subprocess.PIPE)
while True:
  line = proc.stdout.readline()
  if line != '':
    do_something
  else:
    break

Entire output at once

echo subprocess.check_output(['/bin/ls', 'something])

Parse JSON in Python

import json
data = json.loads(json_string)

Convert YAML to JSON

import yaml, json

with open('./file.yaml') as f:
    print(json.dumps(yaml.load(f)))