6a781e06da
Inserted missing words in the article and comments Updated the capitalization of True and False where necessary to maintain consistency with Python syntax
104 lines
3.3 KiB
Markdown
104 lines
3.3 KiB
Markdown
---
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title: If / Elif / Else Statements
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---
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## If / Elif / Else Statements
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The `if`/`elif`/`else` structure is a common way to control the flow of a program, allowing you to execute specific blocks of code depending on the value of some data. If the condition following the keyword `if` evaluates as `True`, the block of code will execute:
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Note that parenthesis is not used before and after the condition check as in other languages.
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```python
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if True:
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print('If block will execute!')
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```
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```python
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x = 5
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if x > 4:
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print("The condition was true!") #this statement executes
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```
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> **Tips** : You can use **1** as alternative to **True** and **0** as an alternative to **False**
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_Example_:
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```python
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if 1: # 1 evaluates to true
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print('If block will execute!')
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```
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You can optionally add an `else` response that will execute if the condition is `False`:
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```python
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if not True:
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print('If statement will execute!')
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else:
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print('Else statement will execute!')
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```
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Or you can also see this example
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```python
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y = 3
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if y > 4:
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print("I won't print!") #this statement does not execute
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else:
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print("The condition wasn't true!") #this statement executes
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```
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*Note that there is no condition following the `else` keyword - it catches all situations where the condition was `False`*
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Multiple conditions can be checked by including one or more `elif` checks after your initial `if` statement but only one condition will execute:
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```python
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z = 7
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if z > 8:
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print("I won't print!") #this statement does not execute
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elif z > 5:
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print("I will!") #this statement will execute
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elif z > 6:
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print("I also won't print!") #this statement does not execute
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else:
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print("Neither will I!") #this statement does not execute
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```
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*Note only the first condition that evaluates as `True` will execute. Even though `z > 6` is `True`, the `if/elif/else` block terminates after the first true condition. This means that an `else` will only execute if none of the conditions were `True`.*
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We can also create nested if statements for decision making. Before preceding please refer to the <a href='https://guide.freecodecamp.org/python/code-blocks-and-indentation' target='_blank' rel='nofollow'>indentation guide once</a> before preceding.
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Let's take an example of finding a number which is even and also greater than '10':
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```
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python
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x = 34
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if x % 2 == 0: # this is how you create a comment and now, checking for even.
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if x > 10:
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print("This number is even and is greater than 10")
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else:
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print("This number is even, but not greater than 10")
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else:
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print ("The number is not even. So point checking further.")
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```
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This was just a simple example for nested if statement. Please feel free to explore more online.
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While the examples above are simple, you can create complex conditions using <a href='https://guide.freecodecamp.org/python/comparisons' target='_blank' rel='nofollow'>boolean comparisons</a> and <a href='https://guide.freecodecamp.org/python/boolean-operations' target='_blank' rel='nofollow'>boolean operators</a>.
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***Inline python if-else statement***
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We can also use if-else statements with inline python functions
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The following example should check if the number is greater or equal than 50, if yes return True:
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```
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python
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x = 89
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is_greater = True if x >= 50 else False
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print(is_greater)
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```
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Output
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```
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>
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True
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>
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```
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