len() - Finding Length

Returns the number of items in a sequence.

1
text = "Hello"
2
print(len(text)) # 5
3

4
empty = ""
5
print(len(empty)) #0
6

7
print(len(range(5))) # 5
8

9
print(len(range(2, 10))) # 8

min() and max() - Finding Minimum and Maximum

The min() function returns the smallest item from a sequence. The max() function returns the largest item.

1
text = "Hello"
2
print(min(text)) # H
3
print(max(text)) # o
4

5
text = "python"
6
print(min(text)) # h
7
print(max(text)) # y
8

9
letters = "ABCabc"
10
print(min(letters)) # A
11
print(max(letters)) # c
12

13
numbers = range(5, 15)
14
print(min(numbers)) # 5
15
print(max(numbers)) # 14

sum() - Adding Numbers

Adds all numbers in an iterable (like a range) and returns the total.

1
print(sum(range(1, 6)))
2

3
print(sum(range(0, 11, 2))) # 30

abs() - Absolute Value

Returns the absolute value of a number. The absolute value is the distance from zero, so it’s always positive (or zero). For complex numbers, the absolute value is the magnitude of the complex number.

1
print(abs(5)) # 5
2
print(abs(-5)) # 5
3

4
print(abs(3 + 4j)) # 5.0

pow() - Power Function

Raises a number to a power. pow(x, y) returns x raised to the power of y.

1
print(pow(2, 3)) # 8
2
print(pow(5, 2)) # 25

It also takes an optional third argument for modular exponentiation pow(x, y, z). Which means that it returns x raised to the power of y modulo z. pow(x, y, z) is equivalent to (x ** y) % z, but it is more efficient.

1
print(pow(2, 3, 5)) # 3
2
print(pow(5, 2, 3)) # 1

round() - Rounding Numbers

Rounds a number to the nearest integer or to a specified number of decimal places.

1
print(round(3.7)) # 4
2
print(round(3.2)) # 3

When a second argument is provided, round() rounds to that many decimal places:

1
print(round(3.14159, 2)) # 3.14
2
print(round(2.71828, 3)) # 2.718

chr() and ord() - Character and Unicode Conversion

The ord() function returns the Unicode code point (an integer) of a single character. The chr() function does the reverse, it returns the character represented by a Unicode code point.

1
print(ord('A')) # 65
2
print(ord('a')) # 97
3
print(ord('0')) # 48
4
print(ord(' ')) # 32
5

6
print(chr(65)) # A
7
print(chr(97)) # a
8
print(chr(48)) # 0
9
print(chr(32)) # (space character)

id() - Object Identity

Returns the unique identifier (memory address) of an object. This is useful for understanding if two variables refer to the same object in memory.

For immutable types like int, float, str, tuple, bool, and None Python often interns or caches small or frequently used objects to save memory, especially for small integers. This means two “equal” immutable objects might actually share the same memory address (and thus the same id()).

1
x = 5
2
y = 5
3
print(id(x))
4
print(id(y))
5
print(id(x) == id(y)) # True
6

7
a = 123456789123456789123456789
8
b = 123456789123456789123456789
9
print(a == b) # True
10
print(id(a) == id(b)) # False
11
a = b
12
print(id(a) == id(b)) # True
13

14
text1 = "Hello"
15
text2 = "Hello"
16
print(id(text1) == id(text2)) # True
17

18
x = "Hello worlddddddddddddddddddddddddddddddddddddddddddddddddddd"
19
y = "Hello worlddddddddddddddddddddddddddddddddddddddddddddddddddd"
20
print(id(x) == id(y)) # False

Exercises

1
text = "Python Programming"
2
print(len(text))

1
print(len(range(0, 15, 3)))

1
text = "Hello World"
2
print(min(text))
3
print(max(text))

1
H
2
r

1
numbers = range(1, 11)
2
print(sum(numbers))

1
print(abs(-10))
2
print(abs(10))
3
print(abs(3 + 4j))
4
print(abs(-2j))

1
10
2
10
3
5.0
4
2.0

1
print(pow(3, 4))
2
print(pow(2, 7, 5))

1
81
2
3

1
print(round(4.6))
2
print(round(4.4))
3
print(round(3.14159, 2))
4
print(round(3.14159, 3))

1
5
2
4
3
3.14
4
3.142

1
code = ord('Z')
2
print(code)
3
print(chr(code - 2))

1
90
2
X