10 Useful Python Snippets

 

1. Swap Two Variables With One Line of Code

Can you think of a way to swap two variables without the help of a third temporary variable? 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

In Python, you can combine comparisons neatly together instead of splitting the statement into two or more parts. 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 neatly unpack a list of elements to separate variables as long as the number of variables remains the same as the number of elements in the list.

For example:

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

Output:

1 2 3

8. One-Liner If-Else Statements

In Python, one-liner if-else statements are known as ternary operators or conditional operators. For example:

age = 30
age_group = "Adult"

if age > 18

else "Child"print(age_group)

Output:

Adult

Generally, a conditional operator follows this pattern for your convenience:

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]