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Quand utiliser plusieurs if par rapport à elif en Python ?

Susan Sarandon
Susan Sarandonoriginal
2024-10-17 13:28:291094parcourir

When to Use Multiple if\'s vs. elif\'s in Python?

Multiple if's vs. elif's in Python

In Python, you may encounter the choice between using multiple if statements or elif statements. While both serve the purpose of branching based on conditions, there are distinct differences to consider.

Multiple if's
In multiple if blocks, each if statement must be separately evaluated. This means the code will check every condition, even if a previous condition has already been met. This can lead to unnecessary computations, especially when you have numerous conditions to check.

For example, consider the following code:

<code class="python">if text == 'sometext':
    print(text)
if text == 'nottext':
    print("notanytext")</code>

In this case, if the text variable is not equal to 'sometext', the code will still evaluate the second if condition, potentially resulting in redundant checks.

elif's
In contrast, elif statements provide a more efficient alternative. With elif, the code checks the first if condition. If it meets the condition, it executes the corresponding code block and skips all subsequent conditions. This eliminates unnecessary evaluations.

For the same example, using elif would look like this:

<code class="python">if text == 'sometext':
    print(text)
elif text == 'nottext':
    print("notanytext")</code>

Here, if the text variable is equal to 'sometext', the code executes the print(text) statement and skips checking the elif condition.

Best Practice
Generally, it is recommended to use elif statements instead of multiple if's for improved efficiency and code readability. By chaining elif conditions, you ensure that only the necessary conditions are evaluated, minimizing unnecessary computations.

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