Variables and Types

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Variables

Variable names may be composed of letters, underscores and, after the first position, also digits.

Lowercase letters are common, but uppercase is also allowed (usually used for constants).

invitation = 'Hello World'
a = 10
b = 3.0
PI = 3.1415

Arithmetical operations

Basic operations and variable assignments:

a = 7
b = 4
c = a-b # 3
d = a*b # 28
e = a/b # 1
f = a%b # modulo, 3
g = a**2 # 49
h = 3.0/b # 0.75
i = 7.0//b # floor div, 1.0

Types

The basic data types in Python are:

  • Boolean (True / False).
  • Integer (0, 1, -3).
  • Float (1.0, -0.3, 1.2345)
  • Strings ('apple', ”banana”) - both single and double quotes are equivalent.
  • None (aka an empty variable).

Type conversions

Variables can be converted using:

  • int(value) → from a float or string.
  • float(value) → from a int or string.
  • str(value) → from any Python variable, including None, any function or object.