25 Essential Python Tricks for Efficient Coding

This article presents a curated list of twenty‑five Python idioms that improve code brevity and performance.

1. In‑place swapping

Python allows simultaneous assignment to swap values without a temporary variable.

x, y = 10, 20
print(x, y)

x, y = y, x
print(x, y)

2. Chained comparisons

Multiple relational checks can be combined in a single expression.

n = 10
result = 1 < n < 20
print(result)  # True
result = 1 > n <= 9
print(result)  # False

3. Ternary operator

Use value_if_true if condition else value_if_false for concise conditional assignments. x = 10 if (y == 9) else 20 It also works inside comprehensions and class instantiation.

[m**2 if m > 10 else m**4 for m in range(50)]

def small(a, b, c):
    return a if a <= b and a <= c else (b if b <= a and b <= c else c)

x = (classA if y == 1 else classB)(param1, param2)

4. Multi‑line strings

Triple quotes simplify multi‑line literals compared to escaped newlines in C.

a = '''dvfssd
fsdfdsfsd
dsdsfbfdfasf
afasfaf'''
print(a)

5. Membership test

Use in to check if an element exists in a collection.

if m in [1,3,5,7]:
    print('found')

# instead of multiple equality checks

6. Four ways to reverse sequences

Reverse a list in place, iterate over a reversed view, slice a string, or slice a list.

testList = [1,3,5]
testList.reverse()
print(testList)  # [5,3,1]

for element in reversed([1,3,5]):
    print(element)

"Test Python"[::-1]  # 'nohtyP tseT'

[1,3,5][::-1]  # [5,3,1]

7. Simultaneous variable initialization

Assign multiple variables in one statement or unpack a list.

a,b,c,d = 1,2,3,4

lst = [1,2,3]
x,y,z = lst
print(x, y, z)

8. Print module path

import socket
print(socket)  # <module 'socket' from '/usr/lib/python2.7/socket.py'>

9. Dictionary and set comprehensions

testDict = {i: i*i for i in range(10)}
testSet = {i*2 for i in range(10)}
print(testSet)
print(testDict)

10. String concatenation

a = "i "
b = "love "
c = "you"
print(a+b+c)

lst = ['a','b','c']
print(''.join(lst))

11. Enumerate with index

lst = [10,20,30]
for i, value in enumerate(lst):
    print(i, ': ', value)

12. Return multiple values

def a():
    return 1,2,3,4,5

13. Quick HTTP file server python3 -m http.server 14. Debugging with pdb

import pdb
pdb.set_trace()

15. Direct iteration over sequences

l = [0,1,2,3,4,5]
for i in l:
    print(i)  # faster than indexing

16. Effective use of else in loops and try

In for / while loops, else runs only when the loop isn’t terminated by break. In try, else runs only if no exception occurs.

for i in l:
    if i == 6:
        break
else:
    print('completed')

try:
    a()
except OSError:
    pass
else:
    print('no error')

17. Exception handling syntax

try:
    risky()
except OSError:
    handle_os()
except (ValueError, TypeError) as e:
    handle_specific(e)
else:
    print('no exception')
finally:
    cleanup()

18. Introspection

Functions like type(), dir(), getattr(), hasattr(), and isinstance() reveal object information at runtime.

19. Container overview

Lists (mutable, ordered), tuples (immutable, ordered, hashable), sets (unordered, unique), and dictionaries (unordered key‑value mapping).

20. map() function

def f(x):
    return x*x
r = map(f, [1,2,3,4,5,6,7,8,9])
print(list(r))

print(list(map(str, [1,2,3,4,5,6,7,8,9])))

21. reduce() function

from functools import reduce

def fn(x, y):
    return x*10 + y
print(reduce(fn, [1,3,5,7,9]))  # 13579

# building an int from a string
char_map = {str(i): i for i in range(10)}

def strint(s):
    return reduce(lambda x, y: x*10 + y, map(char_map.get, s))

22. split() method

text = "a b c"
parts = text.split()

23. Theory meets practice

Combine learned tricks to solve typical interview problems, such as reversing word order in a sentence. print(" ".join(input().split()[::-1])) Another example merges two integer arrays, removes duplicates, and sorts them:

a,b,c,d = input(), list(map(int, input().split())), input(), list(map(int, input().split()))
print("".join(map(str, sorted(set(b+d)))))

And removing duplicate digits from a reversed integer:

result = ""
for i in input()[::-1]:
    if i not in result:
        result += i
print(result)

24. filter() function

def is_odd(n):
    return n % 2 == 1
print(list(filter(is_odd, [1,2,4,5,6,9,10,15])))

# Sieve of Eratosthenes using filter

def _odd_iter():
    n = 1
    while True:
        n += 2
        yield n

def _not_divisible(n):
    return lambda x: x % n > 0

def primes():
    yield 2
    it = _odd_iter()
    while True:
        n = next(it)
        yield n
        it = filter(_not_divisible(n), it)

25. sorted() function

sorted([36,5,-12,9,-21])
sorted([36,5,-12,9,-21], key=abs)
sorted(['bob','about','Zoo','Credit'])
sorted(['bob','about','Zoo','Credit'], key=str.lower)
sorted(['bob','about','Zoo','Credit'], key=str.lower, reverse=True)

The article continuously updates these fundamental Python techniques to help developers write cleaner, faster, and more maintainable code.