Python Comparison Operators

5 Key excerpts on "Python Comparison Operators"

• 

  eBook - ePub

  Hands on Data Science for Biologists Using Python

  • Yasha Hasija, Rajkumar Chakraborty(Authors)
  • 2021(Publication Date)
  • CRC Press

    (Publisher)

  Until this point, we have recognized our programs as straightforward, but these did not seem to be smart, nor did these make any decisions. If we want a program to make decisions based on some conditions, then it will require conditional statements. Computers have only two conditions - “True” or “False” - similar to a light switch that has two conditions - “On” or “Off”. Therefore, these “True” and “False” conditions constitute a particular datatype in Python referred to as Booleans.

  Defining a condition always requires some kind of comparison - such as greater than, less than, or equal to. Some of the comparisons with their operators in Python are given below:

  • Equal: a = = b

  • Not Equal: a!= b

  • Less than: a < b

  • Less than or equal to: a < = b

  • Greater than: a > b

  • Greater than or equal to: a > = b

  All of these comparisons result in the Boolean values “True” or “False”.

  Code:

  #Booleans expressions and comparisons # Comparing integers print(100 = =100) print(100 = =101) print(200 > 100) print(200 < 100) # Comparing strings print('hello'=='hello') print('hello'=='hey') print('hello'!='hey')

  Output:

  True False True False True False True

  We can compare any datatype in Python - including comparisons between integers and strings - as illustrated in the example above. In the output, we have “True” and “False”. These are not a string of characters; rather, they are predefined keywords of Python and are of the bool type.

  Code:

  # True and False are not strings, they are bools print(type(100 = =100)) print(type(100 = =101)) print(type(True)) print(type(False))

  Output:

  <class 'bool'> <class 'bool'> <class 'bool'> <class 'bool'>

  Logical Operators

  When we have to compare multiple conditions, we have to use a logical operator. Python has three logical operators - “and”, “or”, and “not” - their meanings in the Python program are the same as their definitions in English. Usually, logical operators operate on the following conditions:

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  eBook - ePub

  Programming with Python for Social Scientists

  • Phillip D. Brooker(Author)
  • 2019(Publication Date)
  • SAGE Publications Ltd

    (Publisher)

  10 #on social science applications for more detail). This becomes especially
• 11 #powerful when we combine it with things like IF, ELIF and ELSE statements
• 12 #(which we will do later), but for now, here are a list of ways in which
• 13 #we can compare things in Python. I have declared three variables below -
• 14 #try typing the comparisons I've listed into the Python shell and see what
• 15 #happens.
• 16
• 17 a = 2
• 18 b = 3
• 19 c = 4
• 20
• 21 a == b #The double-equals signifies an "is the same as" comparison.
• 22 a != b #This signifies a "not the same as" comparison
• 23
• 24 b > a #"is greater than"
• 25 b >= a #"is greater than or equal to"
• 26
• 27 b < a #"is less than"
• 28 b <= a #"is less than or equal to"
• 29
• 30 c % a #This is called the "modulo", which effectively means the remainder.
• 31  #So here, the value that will be given when you type this into the Python
• 32  #shell will be the remainder that is left over when c is divided by a. The
• 33  #modulo is more of a calculation than a comparator, but it's mainly
• 34  #only relevant to us as a way of comparing things.
• 35  
• 36  
• 37 #QUESTION: You can also do calculations within comparisons. Can you guess what
• 38 #will result in the following cases? Have a guess, then type them into the
• 39 #Python shell to check.
• 40
• 41 a+1 == b
• 42
• 43 c-1 >= b
• 44
• 45 c/4 > a
• 46
• 47 a*2 == c
• 48
• 49 c % a == 0