1. any and all

all(): # return True if all elements of the iterable are truthy(or if the iterable is empty)

print(all([0,1,2,3])) #False

print(all([])) #True

print(all([char for char in "eio" if char in "aeiou"])) #True

print(all([num for num in [1,2,3] if num %2 == 0 ])) #True

print(all([num for num in [0,2,3] if num %2 == 0 ])) #False

people =["calr", "cass"]

print(all (name[0] == "c" for name in people)) ##True

any(): return True if any elements of the iterable are truthy (if the iterable is empty--false)

print(any([0,1,2,3])) #True

print(any([])) #False

2.generator expression

print(type((name[0] == "c" for name in people))) #<class 'generator'>

# save space, memory, if you only need it once, don't need a list(comprehension) to store then you can use it

import sys

# A simple comparison of size (in Bytes)

list_comp = sys.getsizeof([x * 10 for x in range(1000)]) #List Comprehension: 9024 byte

gen_exp = sys.getsizeof(x * 10 for x in range(1000)) # Generator Expression: 120 bytes

#Using a Generator Expression

def is_all_strings(lst):

return all(type(l) == str for l in lst)

#Using a List Comprehension

def is_all_strings(lst):

return all([type(l) == str for l in lst])

3.sorted()

#sorted() returns a new sorted list from the items in iterable

#remember nums.sort() is inplace()!!! -- which is also a list specific method, can't use on other objects

#sorted method can accept iterable stuff even it is a tuple

more_numbers = [6,1,8,2]

new_numbers = sorted(more_numbers)

new_numbers2 = sorted(more_numbers, reverse = True)

print(more_numbers) #[6, 1, 8, 2]

print(new_numbers) #[1, 2, 6, 8]

print(new_numbers2) # [8, 6, 2, 1]

print(sorted((1,56,3,76))) # [1, 3, 56, 76]

users = [

{"username": "samuel", "tweets": ["I love cake", "I love pie", "hello world!"]},

{"username": "katie", "tweets": ["I love my cat"]},

{"username": "jeff", "tweets": [], "color": "purple"},

{"username": "bob123", "tweets": [], "num": 10, "color": "teal"},

{"username": "doggo_luvr", "tweets": ["dogs are the best", "I'm hungry"]},

{"username": "guitar_gal", "tweets": []}

]

sorted(users, key = len)

# To sort users by their username---for each user in users check the ["username"]

sorted(users,key=lambda user: user['username'])

# Finding our most active users...

# Sort users by number of tweets, descending

sorted(users,key=lambda user: len(user["tweets"]), reverse=True)

sorted(iterable, key=key, reverse=reverse) -> return a new list

iterable Required. The sequence to sort, list, dictionary, tuple etc.

key Optional. A Function to execute to decide the order. Default is None

reverse Optional. A Boolean. False will sort ascending, True will sort descending. Default is False

4. max() and min()

max() # return the largest item in an iterable or the largest of two or more arguments

print(max(1,43,6)) #43

print(max("awesome world")) #w

print(min("awesome world")) #" " ---空格更小

names = ['Arya', "Samson", "Dora", "Tim"]

print(min(names)) #Arya

print(max(names)) #Tim--直接还是按照alphabetally的不是按照字符长度先排

print(min(names, key = lambda n: len(n))) #Tim

print(min(len(n) for n in names)) #3

5.reversed() #not reverse !

reversed(0 # return a reverse iterator

#reverse is just for list, also inplace

#这俩是一样的都是4-0

for x in reversed(range(0,5)) :

print(x)

for x in range(4,-1,-1): #注意range倒数也还是需要顺序反着写，包左不包右依然存在

print(x)

5.len()

'hello'__len__() //double underscore ---you can implement it by yourself; this is called by len() -- define your own len()