111 lines
1.8 KiB
Markdown
111 lines
1.8 KiB
Markdown
---
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tags: [python]
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---
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# Loops in Python
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## For
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There are three main types of `for` loop in Python and they all use the
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`for...in` clause:
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1. Traditional `for` loop with range:
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```py
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for i in range(0, 5):
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print(i)
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```
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This is equivalent to the following in JavaScript:
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```js
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for (let i = 0; i <= 5: i++) {
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console.log(i)
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}
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```
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2. `for` loop with iterable:
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```py
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fruits = ["apple", "banana", "cherry"]
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for (fruit in fruits):
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print(fruit)
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```
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3. `for` loop with `enumerate()` function: Iterate over an iterable whilst also
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keeping track of the index of the current element:
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```py
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for index, fruit in enumerate(fruits):
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print(f"Index {index}: {fruit}")
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```
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### Loop in increments greater than 1
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The following loop increments by 2 on each iteration
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```py
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for i in range(0, 10, 2):
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print(i, ' ', end='')
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print()
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# 0 2 4 6 8
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```
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### Break and continue
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#### Break
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```py
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num = int(input('Enter a number from 1-6 to check for: '))
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for i in range(0, 6):
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if i == num:
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break
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print(i, ' ')
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```
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#### Continue
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```py
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for i in range(0, 10):
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print(i, ' ', end='')
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if i % 2 == 1:
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continue
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print('hey its an even number')
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print('we love even numbers')
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print('Done')
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"""
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0 hey its an even number
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we love even numbers
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1 2 hey its an even number
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we love even numbers
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3 4 hey its an even number
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we love even numbers
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5 6 hey its an even number
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we love even numbers
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7 8 hey its an even number
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we love even numbers
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9 Done
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"""
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```
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## While
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```python
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count = 0
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print('Starting')
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while count < 10:
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print(count, '', end='')
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count += 1
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print() # not part of the while loop
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print('Done')
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"""
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Starting
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0 1 2 3 4 5 6 7 8 9
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Done
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"""
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```
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> There are no `do while` loops in Python
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