"""This module contains a code example related to
Think Python, 2nd Edition
by Allen Downey
http://thinkpython2.com
Copyright 2015 Allen Downey
License: http://creativecommons.org/licenses/by/4.0/
"""
from __future__ import print_function, division
import random
def nested_sum(t):
"""Computes the total of all numbers in a list of lists.
t: list of list of numbers
returns: number
"""
total = 0
for nested in t:
total += sum(nested)
return total
def cumsum(t):
"""Computes the cumulative sum of the numbers in t.
t: list of numbers
returns: list of numbers
"""
total = 0
res = []
for x in t:
total += x
res.append(total)
return res
def middle(t):
"""Returns all but the first and last elements of t.
t: list
returns: new list
"""
return t[1:-1]
def chop(t):
"""Removes the first and last elements of t.
t: list
returns: None
"""
del t[0]
del t[-1]
def is_sorted(t):
"""Checks whether a list is sorted.
t: list
returns: boolean
"""
return t == sorted(t)
def is_anagram(word1, word2):
"""Checks whether two words are anagrams
word1: string or list
word2: string or list
returns: boolean
"""
return sorted(word1) == sorted(word2)
def has_duplicates(s):
"""Returns True if any element appears more than once in a sequence.
s: string or list
returns: bool
"""
# make a copy of t to avoid modifying the parameter
t = list(s)
t.sort()
# check for adjacent elements that are equal
for i in range(len(t)-1):
if t[i] == t[i+1]:
return True
return False
def main():
t = [[1, 2], [3], [4, 5, 6]]
print(nested_sum(t))
t = [1, 2, 3]
print(cumsum(t))
t = [1, 2, 3, 4]
print(middle(t))
chop(t)
print(t)
print(is_sorted([1, 2, 2]))
print(is_sorted(['b', 'a']))
print(is_anagram('stop', 'pots'))
print(is_anagram('different', 'letters'))
print(is_anagram([1, 2, 2], [2, 1, 2]))
print(has_duplicates('cba'))
print(has_duplicates('abba'))
if __name__ == '__main__':
main()