Loop Control Statements in a while Loop

The break and continue statements are powerful tools for controlling the flow of a while loop:

break: immediately exits the loop when a specific condition is met;
continue: skips the rest of the current iteration and moves to the next one.

Additionally, the pass statement is used as a placeholder and does nothing when executed, which can be useful for incomplete logic or avoiding errors in empty blocks.

Let's use a while loop to search for a specific city in the travel_list. If the city is found, the loop will terminate using break.


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travel_list = ['Monako', 'Luxemburg', 'Liverpool', 'Barcelona', 'Munchen']

# Initialize the index
i = 0

# Search for "Barcelona"
while i < len(travel_list):
    if travel_list[i] == 'Barcelona':
        print('Found Barcelona!')
        break
    print(travel_list[i])
    i += 1

The index i starts at 0, pointing to the first city in the list;
The while loop continues as long as i is less than the length of travel_list;
If the current city is "Barcelona", the message is printed, and the loop exits using break and "Munchen" is never reached by the loop;
If "Barcelona" is not found, the current city is printed, and i is incremented to move to the next city.

Now, let's count how many times "Barcelona" appears in the travel_list, skipping cities that don't match using continue.


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travel_list = ['Monako', 'Barcelona', 'Liverpool', 'Barcelona', 'Munchen', 'Barcelona']

# Initialize variables
i = 0
counter = 0

# Count occurrences of "Barcelona"
while i < len(travel_list):
    if travel_list[i] != 'Barcelona':
        i += 1
        continue
    else:
        counter += 1
    i += 1

print('Total occurrences of Barcelona:', counter)

The index i starts at 0, and counter is set to 0 to track occurrences of 'Barcelona';
The while loop runs as long as i is less than the length of travel_list;
If the current city is not 'Barcelona', the loop skips the remaining code for that iteration using continue and increments i;
For each occurrence of 'Barcelona', counter is incremented, and the loop continues until all cities are checked.

Taak

Swipe to start coding

You are organizing a country database and need to filter out only the countries that start with the letter 'S'. However, to keep the list manageable, you decide to limit the selection to just 3 countries.

Iterate through the countries list using a while loop.
Skip any country that does not start with 'S'.
Add only the first 3 valid countries to the selected list.

Oplossing

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Was alles duidelijk?

Bedankt voor je feedback!

Sectie 2. Hoofdstuk 4

Loop Control Statements in a while Loop

The break and continue statements are powerful tools for controlling the flow of a while loop:

break: immediately exits the loop when a specific condition is met;
continue: skips the rest of the current iteration and moves to the next one.

Additionally, the pass statement is used as a placeholder and does nothing when executed, which can be useful for incomplete logic or avoiding errors in empty blocks.

Let's use a while loop to search for a specific city in the travel_list. If the city is found, the loop will terminate using break.


              123456789101112
            
travel_list = ['Monako', 'Luxemburg', 'Liverpool', 'Barcelona', 'Munchen']

# Initialize the index
i = 0

# Search for "Barcelona"
while i < len(travel_list):
    if travel_list[i] == 'Barcelona':
        print('Found Barcelona!')
        break
    print(travel_list[i])
    i += 1

The index i starts at 0, pointing to the first city in the list;
The while loop continues as long as i is less than the length of travel_list;
If the current city is "Barcelona", the message is printed, and the loop exits using break and "Munchen" is never reached by the loop;
If "Barcelona" is not found, the current city is printed, and i is incremented to move to the next city.

Now, let's count how many times "Barcelona" appears in the travel_list, skipping cities that don't match using continue.


              12345678910111213141516
            
travel_list = ['Monako', 'Barcelona', 'Liverpool', 'Barcelona', 'Munchen', 'Barcelona']

# Initialize variables
i = 0
counter = 0

# Count occurrences of "Barcelona"
while i < len(travel_list):
    if travel_list[i] != 'Barcelona':
        i += 1
        continue
    else:
        counter += 1
    i += 1

print('Total occurrences of Barcelona:', counter)

The index i starts at 0, and counter is set to 0 to track occurrences of 'Barcelona';
The while loop runs as long as i is less than the length of travel_list;
If the current city is not 'Barcelona', the loop skips the remaining code for that iteration using continue and increments i;
For each occurrence of 'Barcelona', counter is incremented, and the loop continues until all cities are checked.

Taak

Swipe to start coding

Iterate through the countries list using a while loop.
Skip any country that does not start with 'S'.
Add only the first 3 valid countries to the selected list.

Oplossing

Schakel over naar desktop voor praktijkervaringGa verder vanaf waar je bent met een van de onderstaande opties

Was alles duidelijk?

Bedankt voor je feedback!

Sectie 2. Hoofdstuk 4

Schakel over naar desktop voor praktijkervaringGa verder vanaf waar je bent met een van de onderstaande opties