Warm Up Exercise

As a warm-up, write a function is_prime that takes an integer n and returns True if n is prime and False otherwise.

def is_prime(n):
  if n < 2:
    return False
  ...

#=> is_prime(1)  == False
#=> is_prime(2)  == True
#=> is_prime(6)  == False
#=> is_prime(73) == True
What is Data

What is Data?

(some fun history)

What is Data

The First Electronic Data

center
What is Data
center
What is Data
center
What is Data
center
What is Data
center
What is Data
What is Data

  • Morse Code

    • "tomorrow will be better"
    • "--- -- --- .-. .-. --- .-- .-- .. .-.. .-.. -... . -... . - - . .-."
    • 140-ish bits

  • Chinese Telegraph Code

    • "明天会更好"
    • ". .-- - . .-. -- --- .-- --. .-. .... .-."
    • 86-ish bits
Data Primitives

Data Primitives

Data Primitives

Data Primitives

  • Integers: 5, -2, 4000237
  • Floats: 3.14, 2.71
  • Characters: 'a', 'b'
  • Boolean: True, False

A "primitive" data type takes up a small fixed amount of space.

Data Primitives

Integers

Decimal Binary
0 00000000
1 00000001
2 00000010
3 00000011
... ...
254 01111110
255 01111111
Data Primitives

center

Data Primitives
1 byte 8 bits −128 to +127
2 bytes 16 bits −32,768 to +32,767
4 bytes 32 bits −2,147,483,648 to +2,147,483,647
8 bytes 64 bits −9,223,372,036,854,775,808 to +9,223,372,036,854,775,807
center
Data Primitives
Data Primitives

Floats

center

Data Primitives

Characters (ASCII)

Characters are just numbers!

Char Number Binary
A 65 01000001
B 66 01000010
... ... ...
Z 90 01011010
a 97 01100001
b 98 01100010
Data Primitives

Booleans

Bools are also just numbers!

Bool Number Binary
False 0 00000000
True 1 00000001
Data Primitives

Converting Between Primitives

>>> ord('a')
97
>>> int(True)
1
>>> chr(65)
'A'
>>> bool(0)
False

_class lead