Prints out all installed packages with their requirements and reverse requirements.

pipdeps.py

#!/usr/bin/env python
from collections import OrderedDict
import pip
import sys


class PackageInfo(object):
    def __init__(self, *args, **kwargs):
        self._info_struct = {}

    @property
    def info(self):
        if not self._info_struct:
            self.process_packages()
        return self._info_struct

    def process_packages(self):
        for item in pip.get_installed_distributions():
            item_name = item.project_name.lower()
            self.ensure_package(item_name)
            self._info_struct[item_name]['version'] = item.version
            for req in item.requires():
                self._info_struct[item_name]['requires'].append(req)
                req_name = req.project_name.lower()
                self.ensure_package(req_name)
                self._info_struct[req_name]['reverse'].append(
                    (item_name, item.version),
                )

    def ensure_package(self, name):
        if name not in self._info_struct.keys():
            self._info_struct[name] = {
                'version': '',
                'requires': [],
                'reverse': [],
            }


def main():
    info = PackageInfo().info
    ordered_info = OrderedDict(sorted(info.items()))
    for key, value in ordered_info.items():
        sys.stdout.write('{} ({}):\n'.format(key, value['version']))
        sys.stdout.write('- Requires:\n')
        for req in value['requires']:
            sys.stdout.write('  - {}\n'.format(req))
        sys.stdout.write('- Reverse:\n')
        for req, version in value['reverse']:
            sys.stdout.write('  - {} ({})\n'.format(req, version))
        sys.stdout.write('\n')


if __name__ == '__main__':
    main()