HOW TO detect STDIN with Python

admin — Mon, 25 Jul 2011 16:00:06 +0000

In Python, as with most languages, STDIN is treated like a file. You can read from it any time, but knowing what kind of file it is lets us know if someone passed us something via STDIN or if we are going to prompt them for it.

import os, sys

if os.isatty(file.fileno(sys.stdin)): print "Reading list from STDIN." print "Enter your list. Press ^D to continue, ^C to quit." my_list = sys.stdin.readlines() else: print "Thank you for passing me a list through a pipe." my_list = sys.stdin.readlines()

Now lets try it two ways:

First, pass it some stuff:
echo mother sister father brother | ./myapp.py

Then try it plain:
./myapp.py

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Python HOWTO Push a Dict on to a List (push a hash on to an array)

admin — Fri, 23 Apr 2010 14:37:37 +0000

One of my more popular posts is How to Push a Hash on to an Array in PERL, but how do you push a dict on to a list in Python?

Lists are one-dimensional arrays and dicts are associative arrays or hash arrays. This means we can do the same thing we do in other languages, with syntax to match Python’s object-oriented data structures.

import pprint

# Define the list somelist = []

# Do add some elements to the list somelist.append({'key1':'value1', 'key2': 'value2'}) somelist.append({'key1':'value1', 'key2': 'value2'}) somelist.append({'key1':'value1', 'key2': 'value2'})

# Print it out pp = pprint.PrettyPrinter(indent=4) pp.pprint(somelist)

Will give you:

[ { 'key1': 'value1', 'key2': 'value2'}, { 'key1': 'value1', 'key2': 'value2'}, { 'key1': 'value1', 'key2': 'value2'}]

Did you find this post useful or have questions or comments? Please let me know!

Brain Goo » python

HOW TO detect STDIN with Python

Python HOWTO Push a Dict on to a List (push a hash on to an array)