01.py

#  This is a comment

'''
   This is a comment
   on multiple lines
'''

#  VARIABLES
#
#  A variable is a symbol that represents a quantity that may vary.
#
#  identifier = value;

age = 25        # The value 25 is assigned to variable age



#  BASIC DATA TYPES
sea_level = 25                            # Integer
temperature = -3.82                       # Real number
name = 'Nacho López'                      # String
has_car = True                            # Boolean (only two values: True or False)



#  ARITHMETIC OPERATIONS WITH NUMBERS
x = 5
y = 2

z = x + y          # Addition.                                     Result: 7.
z = x - y          # Subtraction.                                  Result: 3.
z = x * y          # Multiplication.                               Result: 10.
z = x / y          # Division.                                     Result: 2.5.
z = x % y          # Modulo (remainder of the integer division).   Result: 1.

z = z + 1          # Increase the value of z by 1.                 Result: 2.
z = z - 1          # Decrease the value of z by 1.                 Result: 1.

z = 50 - x * 6 / -0.5          #
z = (50 - x) * 6 / -0.5        # The order of operations is as in mathematics
z = (50 - x * 6) / -0.5        #

z = 2 * z + 3                  # Remember: the symbol = assigns a value to the variable



#  BASIC OPERATIONS WITH STRINGS
a = 'GNU/'
b = 'Linux'
c = a + b                                      # Concatenation     Result: 'GNU/Linux'.
c = a * 3                                      # Repetition        Result: 'GNU/GNU/GNU/'.



#  PRINT VARIABLES ON SCREEN

print('Hello, world!')                   # Prints on screen: Hello, world!
print(x)                                 # Prints the variable x

#  You can print on screen strings and variables
print('I have bought', x, 'oranges and', y, 'lemons.')



#  DATA TYPE CONVERSION

position = '5'
calories = '95.4'
altitude = -544.432

position_int = int(position)               # Convert to integer.
calories_flt = float(calories)             # Convert to float.
altitude_str = str(altitude)               # Convert to string.

position_type = type(position_int)         # Type: integer.
calories_type = type(calories_flt)         # Type: float.
altitude_type = type(altitude_str)         # Type: string.