Code With Python

🔰 For Loop In Python (10 Best Tips & Tricks)

Here are 10 tips to help you write cleaner, more efficient, and more "Pythonic" for loops.

---

1️⃣. Use enumerate() for Index and Value

Instead of using range(len(sequence)) to get an index, enumerate gives you both the index and the item elegantly.

# Less Pythonic 👎
items = ["a", "b", "c"]
for i in range(len(items)):
    print(i, items[i])

# More Pythonic 👍
for i, item in enumerate(items):
    print(i, item)

---

2️⃣. Use zip() to Iterate Over Multiple Lists

To loop through two or more lists at the same time, zip() is the perfect tool. It stops when the shortest list runs out.

names = ["Alice", "Bob", "Charlie"]
ages = [25, 30, 35]

for name, age in zip(names, ages):
    print(f"{name} is {age} years old.")

---

3️⃣. Iterate Directly Over Dictionaries with .items()

To get both the key and value from a dictionary, use the .items() method. It's much cleaner than accessing the key and then looking up the value.

# Less Pythonic 👎
config = {"host": "localhost", "port": 8080}
for key in config:
    print(key, "->", config[key])

# More Pythonic 👍
for key, value in config.items():
    print(key, "->", value)

---

4️⃣. Use List Comprehensions for Simple Loops

If your for loop just creates a new list, a list comprehension is almost always a better choice. It's more concise and often faster.

# Standard for loop
squares = []
for i in range(5):
    squares.append(i * i)
# squares -> [0, 1, 4, 9, 16]

# List comprehension 👍
squares_comp = [i * i for i in range(5)]
# squares_comp -> [0, 1, 4, 9, 16]

---

5️⃣. Use the _ Underscore for Unused Variables

If you need to loop a certain number of times but don't care about the loop variable, use _ as a placeholder by convention.

# I don't need 'i', I just want to repeat 3 times
for _ in range(3):
    print("Hello!")

---

6️⃣. Unpack Tuples Directly in the Loop

If you're iterating over a list of tuples or lists, you can unpack the values directly into named variables for better readability.

points = [(1, 2), (3, 4), (5, 6)]

# Unpacking directly into x and y
for x, y in points:
    print(f"x: {x}, y: {y}")

---

7️⃣. Use break and a for-else Block

A for loop can have an else block that runs only if the loop completes without hitting a break. This is perfect for search operations.

numbers = [1, 3, 5, 7, 9]

for num in numbers:
    if num % 2 == 0:
        print("Even number found!")
        break
else:  # This runs only if the 'break' was never hit
    print("No even numbers in the list.")

---

8️⃣. Iterate Over a Copy to Safely Modify

Never modify a list while you are iterating over it directly. This can lead to skipped items. Instead, iterate over a copy.

# This will not work correctly! 👎
numbers = [1, 2, 3, 2, 4]
for num in numbers:
    if num == 2:
        numbers.remove(num) # Skips the second '2'

# Correct way: iterate over a slice copy [:] 👍
numbers = [1, 2, 3, 2, 4]
for num in numbers[:]:
    if num == 2:
        numbers.remove(num)
print(numbers) # [1, 3, 4]

---

9️⃣. Use reversed() for Reverse Iteration

To loop over a sequence in reverse, use the built-in reversed() function. It's more readable and efficient than creating a reversed slice.

❤2👍1

979 views19:01

# Less readable
items = ["a", "b", "c"]
for item in items[::-1]:
    print(item)

# More readable 👍
for item in reversed(items):
    print(item)

---

🔟. Use continue to Skip the Rest of an Iteration

The continue keyword ends the current iteration and moves to the next one. It's great for skipping items that don't meet a condition, reducing nested if statements.

# Using 'if'
for i in range(10):
    if i % 2 == 0:
        print(i, "is even")

# Using 'continue' can be cleaner
for i in range(10):
    if i % 2 != 0:
        continue  # Skip odd numbers
    print(i, "is even")

━━━━━━━━━━━━━━━
By: @DataScience4 ✨

❤5

1.12K views19:01

✨ How to Build the Python Skills That Get You Hired ✨

📖 Build a focused learning plan that helps you identify essential Python skills, assess your strengths, and practice effectively to progress.

🏷️ #basics #career

❤4

1.09K views21:25

https://t.me/addlist/8_rRW2scgfRhOTc0

This channels is for Programmers, Coders, Software Engineers.

0️⃣ Python
1️⃣ Data Science
2️⃣ Machine Learning
3️⃣ Data Visualization
4️⃣ Artificial Intelligence
5️⃣ Data Analysis
6️⃣ Statistics
7️⃣ Deep Learning
8️⃣ programming Languages

✅

✅

https://t.me/Codeprogrammer

Please open Telegram to view this post

VIEW IN TELEGRAM

❤2

1.2K views11:10

✨ ptpython | Python Tools ✨

📖 An enhanced interactive REPL for Python.

🏷️ #Python

❤4

1.15K views12:03

✨ Pipenv | Python Tools ✨

📖 A dependency and virtual environment manager for Python.

🏷️ #Python

❤4

1.14K views12:18

https://t.me/DataScience4

❌

YOU CAN'T USE LAMBDA LIKE THIS IN PYTHON

The main mistake is turning lambda into a logic dump: adding side effects, print calls, long conditions, and calculations to it.

Such lambdas are hard to read, impossible to debug properly, and they violate the very idea of being a short and clean function. Everything complex should be moved into a regular function. Subscribe for more tips every day !

# you can't do this - lambda with state changes
data = [1, 2, 3]
logs = []

# dangerous antipattern
process = lambda x: logs.append(f"processed {x}") or (x * 10)

result = [process(n) for n in data]

print("RESULT:", result)
print("LOGS:", logs)

🔰

Please open Telegram to view this post

VIEW IN TELEGRAM

❤6👏1

1.2K views13:03

Python Cheat Sheet: The Ternary Operator

🚀

Shorten your if/else statements for compact, one-line value selection. It's also known as a conditional expression.

#### 📜 The Standard if/else Block

This is the classic, multi-line way to assign a value based on a condition.

# Check if a user is an adult
age = 20
status = ""

if age >= 18:
    status = "Adult"
else:
    status = "Minor"

print(status)
# Output: Adult

---

#### ✅ The Ternary Operator (One-Line if/else)

The same logic can be written in a single, clean line.

Syntax:
value_if_true if condition else value_if_false

Let's rewrite the example above:

age = 20

# Assign 'Adult' if age >= 18, otherwise assign 'Minor'
status = "Adult" if age >= 18 else "Minor"

print(status)
# Output: Adult

---

💡

More Examples

The ternary operator is an expression, meaning it returns a value and can be used almost anywhere.

1. Inside a Function return

def get_fee(is_member):
    # Return 5 if they are a member, otherwise 15
    return 5.00 if is_member else 15.00

print(f"Your fee is: ${get_fee(True)}")
# Output: Your fee is: $5.0
print(f"Your fee is: ${get_fee(False)}")
# Output: Your fee is: $15.0

2. Inside an f-string or print()

is_logged_in = False

print(f"User status: {'Online' if is_logged_in else 'Offline'}")
# Output: User status: Offline

3. With List Comprehensions (Advanced)

This is where it becomes incredibly powerful for creating new lists.

numbers = [1, 10, 5, 22, 3, -4]

# Create a new list labeling each number as "even" or "odd"
labels = ["even" if n % 2 == 0 else "odd" for n in numbers]
print(labels)
# Output: ['odd', 'even', 'odd', 'even', 'odd', 'even']

# Create a new list of only positive numbers, or 0 for negatives
sanitized = [n if n > 0 else 0 for n in numbers]
print(sanitized)
# Output: [1, 10, 5, 22, 3, 0]

---

🧠

When to Use It (and When Not To!)

• DO use it for simple, clear, and readable assignments. If it reads like a natural sentence, it's a good fit.

• DON'T use it for complex logic or nest them. It quickly becomes unreadable.

❌

BAD EXAMPLE (Avoid This!):

# This is very hard to read!
x = 10
message = "High" if x > 50 else ("Medium" if x > 5 else "Low")

✅

BETTER (Use a standard if/elif/else for clarity):

x = 10
if x > 50:
    message = "High"
elif x > 5:
    message = "Medium"
else:
    message = "Low"

━━━━━━━━━━━━━━━
By: @DataScience4

✨

Please open Telegram to view this post

VIEW IN TELEGRAM

❤9👍4🔥1

1.4K viewsedited 16:36

"Data Structures and Algorithms in Python"

In this book, which is over 300 pages long, all the main data structures and algorithms are excellently explained.
There are versions for both C++ and Java.

Here's a copy for Python

https://t.me/DataScience4

✅

Please open Telegram to view this post

VIEW IN TELEGRAM

Please open Telegram to view this post

VIEW IN TELEGRAM

❤7

1.16K views06:43

🌟 Join @DeepLearning_ai & @MachineLearning_Programming! 🌟
Explore AI, ML, Data Science, and Computer Vision with us. 🚀

💡 Stay Updated: Latest trends & tutorials.
🌐 Grow Your Network: Engage with experts.
📈 Boost Your Career: Unlock tech mastery.

Subscribe Now!
➡️ @DeepLearning_ai
➡️ @MachineLearning_Programming

Step into the future—today! ✨

❤5

1.17K views12:05

This media is not supported in your browser

0:09

VIEW IN TELEGRAM

🐍

A visualizer that shows the code's execution

The tool allows you to run code directly in the browser and see its step-by-step execution: object creation, reference modification, call stack operation, and data movement between memory areas.

There's also a built-in AI assistant, which you can ask to explain why the code behaves the way it does, or to break down an incomprehensible piece of someone else's solution.

⛓

Link to the service

tags: #useful #python

➡

https://t.me/DataScience4

Please open Telegram to view this post

VIEW IN TELEGRAM

❤7

1.47K viewsedited 13:04

✨ PyInstaller | Python Tools ✨

📖 A freezing tool that bundles Python applications for distribution.

🏷️ #Python

❤2

1.31K views15:04

Python tip:

To create fields that should not be included in the generated init method, use field(init=False).
This is convenient for computed attributes.

Example below 👇

from dataclasses import dataclass, field

@dataclass
class Rectangle:
    width: int
    height: int
    area: int = field(init=False)

    def __post_init__(self):
        self.area = self.width * self.height

👉

@DataScience4

Please open Telegram to view this post

VIEW IN TELEGRAM

❤4

1.11K viewsedited 06:48

A collection of useful built-in Python functions that most juniors haven't touched

1️⃣

all and any: a mini rule engine
— all(iterable) returns True if all elements are true
— any(iterable) returns True if at least one is true
Example:

password = "P@ssw0rd123"
checks = [
    len(password) >= 8,
    any(c.isdigit() for c in password),
    any(c.isupper() for c in password),
]

if all(checks):
    print("password is ok")

— You can quickly build readable policy checks without a forest of ifs

2️⃣

enumerate: a handy counter instead of manual indexing
Instead of for i in range(len(list)):

users = ["alice", "bob", "charlie"]
for idx, user in enumerate(users, start=1):
    print(idx, user)

— You get both the index and the value at once. Less chance to shoot yourself in the foot with off-by-one errors

3️⃣

zip: linking multiple sequences

names  = ["alice", "bob", "charlie"]
scores = [10, 20, 15]
for name, score in zip(names, scores):
    print(name, score)

— You can glue several lists into one stream of tuples, do parallel iteration, nicely combine data without manual indices

4️⃣

reversed: reverse without copying

data = [1, 2, 3, 4]
for x in reversed(data):
    print(x)

— reversed returns an iterator, not a new list, which is convenient when you don't want to allocate extra memory

5️⃣

set and frozenset: uniqueness and fast lookup

items = ["a", "b", "a", "c"]
unique = set(items)  # {'a', 'b', 'c'}
if "b" in unique:
    ...

— A great way to kill duplicates and speed up membership checks, plus frozenset is hashable

👩‍💻

@DataScience4

Please open Telegram to view this post

VIEW IN TELEGRAM

❤14

1.4K viewsedited 10:19

✨ Sphinx | Python Tools ✨

📖 A documentation generator for Python.

🏷️ #Python

❤6

1.39K views12:02

🐍 Fun Illustration of Python List Methods 🎯

https://t.me/DataScience4

⭐

Please open Telegram to view this post

VIEW IN TELEGRAM

❤6👏4

1.44K views20:12

Follow this link to join a group on Signal Messenger.

I'm pleased to invite you to join my private Signal group.

All my resources will be free and unrestricted there. My goal is to build a clean community exclusively for smart programmers, and I believe Signal is the most suitable platform for this (Signal is the second most popular app after WhatsApp in the US), making it particularly suitable for us as programmers.

https://signal.group/#CjQKIPcpEqLQow53AG7RHjeVk-4sc1TFxyym3r0gQQzV-OPpEhCPw_-kRmJ8LlC13l0WiEfp

signal.group

Signal Messenger Group

1.46K views06:36

✨ Conda | Python Tools ✨

📖 A cross-platform package and environment manager for Python.

🏷️ #Python

1.28K views12:03