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Introduction to Python
course content

Course Content

Introduction to Python

Introduction to Python

1. First Acquaintance
The Very First StepsCommentsSome Simple MathMore Challenging MathChallengeBringing It All Together
2. Variables and Types
Storing NumbersNaming RulesUsing VariablesData TypesNumbersChallengeStoring TextString IndexingNegative Indexing and LengthString SlicingChallengeConcatenation
3. Conditional Statements
Boolean Data TypeChallenge: Comparison OperatorsCombining ConditionsChallenge: Logical OperatorsMembership Operators and Types ComparisonSimple if/else ExpressionsChallenge: Grocery StoreChallenge: Odd and Evenif/elif/else ExpressionsChallenge: Grocery Store ExtendedChallenge: Positive, Negative or Zero
4. Other Data Types
What Is a List?List MethodsChallengeNested ListsChallengeWhat Is a Tuple?Tuple MethodsChallengeNested TuplesChallengeWhat Is a Dictionary?ChallengeDictionary MethodsChallenge
5. Loops
while LoopChallengefor LoopChallengeRangeChallengeIterating Over IndexesNested Loops
6. Functions
Built-in FunctionsChallengeDefining Your First FunctionChallengeif/else Statements in FunctionsChallengeFunctions With No ReturnChallengeModifying FunctionsChallengeLambda FunctionsChallenge

bookfor Loop

When you need to loop through a specific set of values, the for loop is your go-to in Python. Unlike some other languages, you don't need a predefined counter variable for this loop. Instead, you use an iterator variable, which you don't have to define ahead of time. Python for loops can work with sequence types, including lists, tuples, strings, and dictionaries. For instance, if you loop through a string:


              
123456

            
# Initial string
word = 'Codefinity'

# Initialize a for loop
for i in word:
  print(i, end = ' ')
copy

Note

In this code, i is a variable that takes on the value of each character in the string word during each iteration of the for loop. As the loop progresses, i sequentially represents each character in 'Codefinity', and each character is printed out.

As shown, the loop runs through each character (or element) of the string. Similarly, when looping through a list, it covers every item in that list.


              
123456

            
# Initial list
values = [1, [2, 3], 4, "code"]

# Initialize a for loop
for el in values:
  print(el, end = ' ')
copy

Note

The for loop doesn't need you to set up a counter variable in advance. You're free to pick any variable name that suits you. Many programmers gravitate towards names like i or j. In our second example, we opted for el, short for 'element'.

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Section 5. Chapter 3
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