How to compare or diff 2 pip freeze or 2 requirements.txt in Python

diff_freeze.py

"""

pip install click

"""

import click
import itertools


def split_package(line):
	result = line.split('==')
	if not len(result) == 2:
		result = line.split('@')

		if not len(result) == 2:
			if line.startswith('-e'):
				# OK, I'll give a try but ONLY if you use the #egg in the end of the str
				result = line.split('#egg=')[1].split('-')
				result = '-'.join(result[:-1]), result[-1]
			else:
				raise Exception('Weird result of splitting: %s' % result)

	return map(lambda x: x.strip(), result)


def packages(freeze_f):
	for line in freeze_f.readlines():
		package, version = split_package(line)
		yield package, version


def merge_packages(*freezes):
	all_keys = set(itertools.chain(*[freeze.keys() for freeze in freezes]))

	for k in all_keys:
		versions = []
		for freeze in freezes:
			versions.append(freeze.get(k, None))  # Add the version for the package

		yield k, versions


def is_unique_value(l):
	"""
	Checks if all elements in l are the same

	:param l: list of str
	"""

	return not l or l.count(l[0]) == len(l)


def compare(old_packages, new_packages):
	"""
	:type old_packages: dict
	:type new_packages: dict
	"""
	requirements = dict(merge_packages(old_packages, new_packages))

	for package_name, versions in requirements.iteritems():
		if not is_unique_value(versions):
			click.echo("{package}: {versions}".format(package=package_name, versions=versions))


@click.command()
@click.argument("old", type=click.File('rb'))
@click.argument("new", type=click.File('rb'))
@click.option('-v', '--verbose', count=True)
def diff(old, new, verbose=False):
	click.echo("Diff between {0} and {1}".format(old, new))
	old_packages = dict(packages(old))
	new_packages = dict(packages(new))
	compare(old_packages, new_packages)


if __name__ == '__main__':
	diff()