variables.md

• In Python, a variable is just a label assigned to a memory that contains a value.
• A variable can point to the value of any data type.
• A value not assigned to a variable (label) is garbage collected.

Declare a variable

a = 1
print(a)
# => 1

Override a value

Variable (label) points to the new value and old value unless pointed by another variable is garbage collected.

a = 1
a = 10
print(a)
# => 10

Declare multiple variable on a single line

b, c = 2, 3
print( b, c )
# => 2 3

Assign same variable

These ariables (labels) point to the same value.

a = b = c = 1
print('a = b = c = 1 => ', a, b, c)
# => a = b = c = 1 =>  1 1 1

Delete a variable

• The del keyword removes the binding between variable name and the value by removing the variable (label).
• The value will be garbage collected unless pointed by another vaiable.

https://stackoverflow.com/questions/21053380/what-does-del-do-exactly)

a = b = 1
del b
print(b)
# => NameError: name 'b' is not defined
print(a)
# => 1

💡 Convention

• Generally use lowercase ASCII letters.
• You can use camelCase or snake_case syntax.
• Use ALL_UPPERCASE letters for global constants (fixed values).
  • Constants do not exist in Python -> https://stackoverflow.com/a/2682752/2790983
• Use _ prefix for _private or _INTERNAL variables and constants.
• Do not start a variable with a digit.