# .css-4zleql{display:block;}Artturi Jalli's Blog  # 10 Useful Python Coding Tricks

Here is a list of useful tips and "tricks" I love to use with Python. Learn these and impress your friends and colleagues.

This list is in no particular order.

## 1. Swap Two Variables With One Line of Code

Can you think of a way to swap two variables without a third? Well, here it is:

``````a = 1
b = 2
a, b = b, a
``````

## 2. Duplicate Strings Without Looping

``````name = "Banana"
print(name * 4)
``````

Output:

``````BananaBananaBananaBanana
``````

## 3. Reverse a String

``````sentence = "This is just a test"
reversed = sentence[::-1]
print(reversed)
``````

Output:

``````tset a tsuj si sihT
``````

## 4. Squash a List of Strings Into One String

``````words = ["This", "is", "a", "Test"]
combined = " ".join(words)
print(combined)
``````

Output:

``````This is a Test
``````

## 5. Comparison Chains

You can combine comparisons together instead of splitting the statement into two or more parts. This works just like you write maths. For example:

``````x = 100
res = 0 < x < 1000
print(res)
``````

Output:

``````True
``````

## 6. Find the Most Frequent Element in a List

``````test = [6, 2, 2, 3, 4, 2, 2, 90, 2, 41]
most_frequent = max(set(test), key = test.count)
print(most_frequent)
``````

Output:

``````2
``````

## 7. Unpack List to Separate Variables

You can unpack a list of elements to variables. Just keep the number of variables the same as the number of list elements.

For instance:

``````arr = [1, 2, 3]
a,b,c = arr
print(a, b, c)
``````

Output:

``````1 2 3
``````

## 8. One-Liner If-Else Statements

You can compress your code by writing some simple if-else's as one-liners. In Python, one-liner if-else statements are called conditional operators. For example:

``````age = 30
age_group = "Adult" if age > 18 else "Child"
print(age_group)
``````

Output:

``````Adult
``````

For your convenience, here is the pattern for using the conditional operator:

``````true_expression if condition else false_expression
``````

## 9. Loop Through a List With One Line of Code

You can use comprehensions to loop through a list with one line of code. For example, let's raise each number in a list to the second power:

``````numbers = [1, 2, 3, 4, 5]
squared_numbers = [num * num for num in numbers]
print(squared_numbers)
``````

Output:

``````[1, 4, 9, 16, 25]
``````

Note: Comprehensions are not just limited to working with lists. You can use comprehensions in a similar one-liner fashion with dictionaries, sets, and generators as well.

Let's see another example by using dictionary comprehension to raise the values of a dictionary to the second power:

``````dict1 = {'a': 1, 'b': 2, 'c': 3, 'd': 4}
squared_dict = {key: num * num for (key, num) in dict1.items()}
print(squared_dict)
``````

Output:

``````{'a': 1, 'b': 4, 'c': 9, 'd': 16}
``````

## 10. Simplify If Statements

Instead of this horrible mess:

``````if n == 0 or n == 1 or n == 2 or n == 3 or n == 4 or n == 5:
``````

You can simply do this:

``````if n in [0, 1, 2, 3, 4, 5]
``````

# Conclusion

Thanks for reading. I hope you find them useful. Happy coding!

#python#software-development#data-science#machine-learning

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