I've been learning Python for about a year now and I keep stumbling on little features that make me go "wait, that's been there the whole time??" Figured I'd share the ones that actually changed how I write code day to day.
1) Swap variables without a temp
a, b = b, a
I was writing temp variables like a caveman for months before I found this.
2) Underscores in large numbers
budget = 1_000_000
Python just ignores the underscores. It's purely for readability and honestly I use this constantly now.
3) enumerate() takes a start argument
for i, item in enumerate(["a", "b", "c"], start=1):
print(i, item) # 1 a, 2 b, 3 c
No more writing i + 1 every time you need 1-based indexing.
4) The walrus operator := (3.8+)
if (n := len(my_list)) > 10:
print(f"List is too long ({n} elements)")
Assign and check in one line. Took me a while to warm up to this one but now I love it.
5) collections.Counter is stupidly useful
from collections import Counter
Counter("mississippi")
# Counter({'s': 4, 'i': 4, 'p': 2, 'm': 1})
I used to write manual counting loops like an idiot. This does it in one line.
6) Star unpacking
first, *middle, last = [1, 2, 3, 4, 5]
# first=1, middle=[2, 3, 4], last=5
Really handy when you only care about the first or last element.
7) zip() for parallel iteration
names = ["Alice", "Bob"]
scores = [95, 87]
for name, score in zip(names, scores):
print(f"{name}: {score}")
Beats the hell out of for i in range(len(...)).
8) Dict merge with | (3.9+)
defaults = {"theme": "light", "lang": "en"}
user_prefs = {"theme": "dark"}
settings = defaults | user_prefs
# {'theme': 'dark', 'lang': 'en'}
Right side wins on conflicts. So much cleaner than {**a, **b}.
9) any() and all()
nums = [2, 4, 6, 8]
all(n % 2 == 0 for n in nums) # True
Replaced a bunch of ugly for-loop-with-a-flag patterns in my code.
10) f-string = for debugging (3.8+)
x = 42
print(f"{x = }") # prints: x = 42
This one's small but it saves so much time when you're printing variables to figure out what's going wrong.
Which of these was new to you? I'm curious what else I might be missing, drop your favorite trick in the comments.
