python codes and answers cheat code pdf

10
2“”
3[]
4

1point = (1, 2, 3)
2point(0:2)     # (1, 2)
3x, y, z = point 
4if 10 in point: 
5    ... 
6 
7# Swapping variables 
8x = 10
9y = 11
10x, y = y, x 
11

1def increment(number, by=1):   
2    return number + by
3 
4# Keyword arguments 
5increment(2, by=1)
6 
7# Variable number of arguments 
8def multiply(*numbers): 
9    for number in numbers: 
10        print number 
11 
12 
13multiply(1, 2, 3, 4)
14 
15# Variable number of keyword arguments 
16def save_user(**user):  
17    ...
18 
19 
20save_user(id=1, name="Mosh")
21

1point = {"x": 1, "y": 2}
2point = dict(x=1, y=2)
3point["z"] = 3
4if "a" in point: 
5    ... 
6point.get("a", 0)   # 0
7del point["x"]
8for key, value in point.items(): 
9   ... 
10 
11# Dictionary comprehensions 
12values = {x: x * 2 for x in range(5)}
13

1if x == 1:  
2    print(“a”)
3elif x == 2:  
4    print(“b”)
5else:   
6    print(“c”)
7 
8# Ternary operator 
9x = “a” if n > 1 else “b”
10 
11# Chaining comparison operators
12if 18 <= age < 65:
13

1from array import array 
2 
3numbers = array("i", [1, 2, 3])
4

1values = (x * 2 for x in range(10000))
2len(values)  # Error
3for x in values: 
4

1# Creating lists
2letters = ["a", "b", "c"]     
3matrix = [[0, 1], [1, 2]]
4zeros = [0] * 5
5combined = zeros + letters
6numbers = list(range(20))
7 
8# Accessing items
9letters = ["a", "b", "c", "d"]
10letters[0]  # "a"
11letters[-1] # "d"
12 
13# Slicing lists 
14letters[0:3]   # "a", "b", "c"
15letters[:3]    # "a", "b", "c"
16letters[0:]    # "a", "b", "c", "d"
17letters[:]     # "a", "b", "c", "d"
18letters[::2]   # "a", "c"
19letters[::-1]  # "d", "c", "b", "a" 
20 
21# Unpacking 
22first, second, *other = letters 
23 
24# Looping over lists 
25for letter in letters: 
26    ... 
27 
28for index, letter in enumerate(letters): 
29    ... 
30 
31# Adding items 
32letters.append("e")
33letters.insert(0, "-")
34 
35# Removing items 
36letters.pop()
37letters.pop(0)
38letters.remove("b")
39del letters[0:3]
40 
41# Finding items 
42if "f" in letters: 
43    letters.index("f")
44 
45# Sorting lists 
46letters.sort()
47letters.sort(reverse=True) 
48 
49# Custom sorting 
50items = [
51    ("Product1", 10),
52    ("Product2", 9),
53    ("Product3", 11)
54]
55 
56items.sort(key=lambda item: item[1])
57 
58# Map and filter 
59prices = list(map(lambda item: item[1], items))
60expensive_items = list(filter(lambda item: item[1] >= 10, items))
61 
62# List comprehensions 
63prices = [item[1] for item in items]
64expensive_items = [item for item in items if item[1] >= 10]
65 
66# Zip function 
67list1 = [1, 2, 3]
68list2 = [10, 20, 30]
69combined = list(zip(list1, list2))    # [(1, 10), (2, 20)]
70

1for n in range(1, 10): 
2    print(n)
3 
4while n < 10: 
5    print(n)
6    n += 1
7

1first = {1, 2, 3, 4}
2second = {1, 5}
3 
4first | second  # {1, 2, 3, 4, 5}
5first & second  # {1}
6first - second  # {2, 3, 4}
7first ^ second  # {2, 3, 4, 5}
8 
9if 1 in first: 
10    ... 
11