Get use count for string prefixes

find_common_prefixes.py

#!/usr/bin/env python3

# Find some suggestions on which shell commands you actually want an alias for:
# cat ~/.bash_history | python3 find_common_prefixes.py | sort -n
# cat ~/.zsh_history | cut -d ';' -f 2  | python3 find_common_prefixes.py | sort -n
import fileinput

class Node():
    def __init__(self, text = ''):
        self.text = text
        self.use_count = 0
        self.children = []

def insert_string(node, s):
    for part in s.split(' '):
        matching_node = None
        for c in node.children:
            if c.text == part:
                matching_node = c
                break
        if not matching_node:
            matching_node = Node(part)
            node.children.append(matching_node)

        matching_node.use_count += 1
        node = matching_node

def print_prefix_and_use_count(node, prefix=''):
    print ('{}\t{}'.format(node.use_count, prefix + ' ' + node.text))

    for child in node.children:
        print_prefix_and_use_count(child, prefix + ' ' + node.text)

def main():
    trie = Node()
    for line in fileinput.input(files=('-')):
        insert_string(trie, line.strip('\n'))

    print_prefix_and_use_count(trie)

main()