OnePythonTip
101 posts
OnePythonTip
@OnePythonTip
Daily bite-sized #Python & #DataScience gems. Maker of cool tees for devs. #MachineLearning #DataAnalytics #Programming #Coding #WebDeveloper
参加日 Temmuz 2023
22 フォロー中1 フォロワー
💡 enumerate() works with ANY iterable.
# Tuples
for i, val in enumerate((10, 20)):
print(i, val) # 0 10, 1 20
# Files
with open("data.txt") as f:
for i, line in enumerate(f, start=1):
print(f"{i}: {line.strip()}") # line numbers!
What do you use enumerate for?
English
Stop using range(len()) to loop through lists.
❌ Ugly:
for i in range(len(list)):
print(i, list[i])
✅ Clean:
for i, item in enumerate(list):
print(i, item)
enumerate() gives you index AND value in one line.
One tip a day. Follow for more.
#Python #LearnToCode 🐍
English
💡 setdefault vs defaultdict:
setdefault: works on ANY dict, one-time default.
defaultdict: needs import, default for ALL missing keys
Use setdefault when you only need default occasionally. Use defaultdict when EVERY missing key needs default. Which one do you use?
English
Counter is a dictionary for counting things.
Manual way:
counts = {}
for item in items:
counts[item] = counts.get(item, 0) + 1
Counter way:
from collections import Counter
counts = Counter(items)
One tip a day. Follow for more.
#Python #DataScience 🐍
English
Flatten nested lists with chain.from_iterable().
Nested = [[1,2], [3,4], [5,6]]
chain.from_iterable (nested)
→ [1,2,3,4,5,6]
Why better than manual loops:
- Faster (C implementation)
- Cleaner
- Memory efficient
One tip a day. Follow for more.
#Python #DataScience 🐍
English
@cached_property computes value ONCE, then caches it. Good for expensive ops.
Example:
class Report:
@cached_property
def sales_data(self):
return database.query("SELECT * FROM sales") # once
One tip a day. Follow for more.
#Python #DataScience 🐍
English
partial creates a new function with some arguments pre-filled.
With partial:
square = partial(power, exponent=2)
Perfect for:
- Specializing general functions
- Callbacks with fixed parameters
- Reducing repetition
One tip a day. Follow for more.
#Python #DataScience 🐍
English
💡 My "pro" moments:
1. Using enumerate() instead of range(len())
2. List comprehensions
3. defaultdict for grouping
4. Writing my first decorator (felt like magic)
What was YOUR moment? Be honest.
#Python #LearnToCode 🐍
English
f-strings can format numbers, dates, and alignment.
Numbers:
{value:.2f} # 2 decimals
{value:,} # commas
{value:.1%} # percentage
Dates:
{now:%Y-%m-%d} # 2026-06-14
Alignment:
{name:<10} # left align
One tip a day. Follow for more.
#Python #DataScience 🐍
English
sorted() with key lets you define custom sorting rules.
Default: sorts by value
Examples:
words = ["cat", "elephant", "dog"]
sorted(words, key=len) # ['cat', 'dog', 'elephant']
One tip a day. Follow for more.
#Python #LearnToCode 🐍
English