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Python basics – operators
1. The Boolean value
A Boolean data type represents one of two values: True or False. Once we start using comparison operators, the use of these data types becomes clear. Unlike JavaScript, the first letter T of True and F of False should be capitalized. Example:
print(True)
print(False)
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2. The operator
The Python language supports many types of operators, and we’ll highlight a few of them.
3. Assignment operators
Assignment operators are used to assign values to variables. Let’s take lambda as an example. An equal sign in mathematics means that two values are equal, but in Python it means that we store a value in some variable, which we call assignment or assignment to the variable. The following table shows the different types of Python assignment operators.
4. Arithmetic operators:
- Addition (+) : A + b
- Subtraction (-) : A – b
- Multiplication (*) : A * b
- Division (/) : A/b
- Modulus (%): A % B
- Floor division (//): A // B
- Exponentiation (**) : A ** b
5. Arithmetic operators
Example: integer
# Arithmetic operations in Python
# integer
print ( 'Addition: ' , 1 + 2 ) # 3
print ( 'Subtraction: ' , 2 - 1 ) # 1
print ( 'Multiplication: ' , 2 * 3 ) # 6
print ( 'Division: ' , 4 / 2 ) # 2.0 Division in Python gives floating point numbers
print ( 'Division: ' , 6 / 2 ) # 3.0
print ('Division: ' , 7 / 2 ) # 3.5
print('Division without the remainder: '.7 // 2) # 3, gives no float or remainder
print ('Division without the remainder: '.7 // 3) # 2
print ( 'Modulus: ' , 3 % 2 ) # 1, give me the remainder
print ( 'Exponentiation: ' , 2 ** 3 )# 9 means 2 * 2 * 2
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Example: floating point number
# floating point number
print ( 'Floating Point Number, PI' , 3.14 )
print ( 'Floating Point Number, Gravity' , 9.81 )
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Example: Plural
# the plural
print ( 'Complex number: ' , 1 + 1j )
print ( 'Multiplying complex numbers: ', (1 + 1j ) * ( 1 - 1j ))
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Let’s declare a variable and assign a numeric data type. I’ll use single-character variables, but remember not to get into the habit of declaring them. Variable names should always be mnemonics.
Example:
Declare the top variable first
a = 3 # a is the variable name and 3 is the integer data type
b = 2 # b is the variable name and 3 is the integer data type
# Do the arithmetic and assign the result to the variabletotal = a + b diff = a - b product = a * b division = a / b remainder = a % b floor_division = a // b exponential = a ** b# I should have used sum instead of total but sum is a built-in function - try to avoid overwriting built-in functions
print ( total ) # If you don't mark your print with some string, you never know where the result is from
print('a + b = ', total)
print('a - b = ', diff)
print('a * b = ', product)
print('a / b = ', division)
print('a % b = ', remainder)
print('a // b = ', floor_division)
print('a ** b = 'Exponentiation) example:print('== Addition, Subtraction, Multiplication, Division, Modulus ==')
Declare values and group them together
num_one = 3
num_two = 4
# Arithmetic operation
total = num_one + num_two
diff = num_two - num_one
product = num_one * num_two
div = num_two / num_one
remainder = num_two % num_one
# with the tag
print('total: ', total)
print('difference: ', diff)
print('product: ', product)
print('division: ', div)
print('remainder: ', remainder)
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Let’s join the dots and start using the calculations we already know (area, volume, density, weight, circumference, distance, force).
Example:
# Calculate the area of a circle
radius = 10 # Radius of the circle
area_of_circle = 3.14 * radius ** 2 # The two * symbols denote exponents or powers
print ( 'Area of a circle: , area_of_circle )
Calculate the area of the rectangle
length = 10
width = 20
area_of_rectangle = length * width
print ( 'Area of a rectangle: , area_of_rectangle )
# Calculate the weight of the object
mass = 75
gravity = 9.81
weight = mass * gravity
print(weight, 'N') # Add the weight of the unit
# Count liquid
mass = 75 # in Kg
volume = 0.075 # in cubic meter
density = mass / volume # 1000 Kg/m^3
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6. Compare operators
In programming we compare values, we use the comparison operator to compare two values. We check if one value is greater than or less than or equal to other values.
Example: Comparison operator
print ( 3 > 2 ) # true, because 3 is greater than 2
print ( 3> =2 ) # true, because 3 is greater than 2
print ( 3 < 2 ) # false, because 3 is greater than 2
print ( 2 < 3 ) # true, because 2 is less than 3
print ( 2< =3 ) # true, because 2 is less than 3
print ( 3= =2 ) # false, because 3 doesn't equal 2
print ( 3! =2 ) # true, because 3 doesn't make 2
print ( len ( 'mango') = =len ( 'avocado' )) # False
print ( len ( 'mango' ) != len ( 'avocado ' )) # True
print ( len ( 'mango' ) < len ( 'avocado' )) # True
print ( len ( 'milk' ) != len ( 'meat' )) # False
print ( len ( 'milk') = =len ( 'meat' )) # True
print ( len ( 'tomato') = =len ( 'potato' )) # True
print ( len ( 'python' ) > len ( 'dragon' )) # False
# Compare something to give true or false
print('True == True: '.True= =True)
print('True == False: '.True= =False)
print('False == False:'.False= =False)
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In addition to the above comparison operators, Python also uses:
- Is: Returns true if two variables are the same object (x is y)
- Is not: Returns true if the two variables are not the same object (x is not y)
- In: Returns True if the query list contains an item (x in y)
- Not in: Returns True if the queried list does not have an item (x in y)
print ( '1 is 1' , 1 is 1 ) # True - Because the data values are the same
print ( '1 is not 2' , 1 is not 2 ) # True - because 1 is not 2
print ( 'A in Asabeneh ' , 'A' in 'Asabeneh' ) # True -a is found in the string
print ( 'B in Asabeneh' , 'B' in 'Asabeneh' ) # False - No capital B
print('coding' in 'coding for all') # True - because of the word coding for all
print ( 'a in an:' , 'a' in 'an' ) # True
print ( '4 is 2 ** 2:' , 4 is 2 ** 2 ) #
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7. Logical operators
Unlike other programming languages, Python uses the keywords AND, or and not for logical operators. Logical operators are used to combine conditional statements:
print ( 3 > 2 and 4 > 3 ) # True - because both statements are True
print ( 3 > 2 and 4 < 3 ) # False - because the second statement is False
print ( 3 < 2 and 4 < 3 ) # False - Because both statements are False
print ( 'True and True: ' , True and True )
print ( 3 > 2 or 4 > 3 ) # True - Because both statements are True
print ( 3 > 2 or 4 < 3 ) # True - Because one of the statements is True
print ( 3 < 2 or 4 < 3 ) # False - Because both statements are False
print ( 'True or False:' , True or False )
print ( not 3 > 2 ) # False - Since 3 > 2 is True, then not True gives False
print (not True ) # False - Negates the not operator that changes true to False
print ( not False ) # True
print ( not not True ) # True
print ( not not False ) # False
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