Speed Up Your Python Code

Learn to use itertools library¶

Python’s Itertools is a module that provides various functions that work on iterators to produce complex iterators. This module works as a fast, memory-efficient tool that is used either by themselves or in combination to form iterator algebra.

Use proper data structure¶

Use of proper data structure has a significant effect on runtime. Python has list, tuple, set and dictionary as the built-in data structures.

However, most of the people use the list in all cases. But it is not a right choice. Use proper data structures depending on your task.

Especially use a tuple instead of a list. Because iterating over tuple is easier than iterating over a list.

Use generators¶

If you have a large amount of data in your list and you need to use one data at a time and for once then use generators. It will save you time.

Use list comprehensions¶

cube_numbers = []
for n in range(0,10):
    if n % 2 == 1:
        cube_numbers.append(n**3)

Don't use such loops, Instead use list comprehension approach as shown below

cube_numbers = [n**3 for n in range(1,10) if n%2 == 1]

Use sets and unions¶

a = [1,2,3,4,5]
b = [2,3,4,5,6]

overlaps = []
for x in a:
  for y in b:
    if x==y:
      overlaps.append(x)

print(overlaps)

This will print the list [2, 3, 4, 5]

Try not using such for nested loops Rather use sets and unions when ever you can

a = [1,2,3,4,5]
b = [2,3,4,5,6]

overlaps = set(a) & set(b)

print(overlaps)

This will print the dictionary {2, 3, 4, 5}

Use `join()` to concatenate strings¶

new = "This" + "is" + "going" + "to" + "require" + "a" + "new" + "string" + "for" + "every" + "word"

Don't use "+" to join strings rather use the str.join method

new = " ".join(["This", "will", "only", "create", "one", "string", "and", "we", "can", "add", "spaces."])

Use multiple assignments¶

Do not assaign variables like this:

a = 2
b = 3
c = 5
d = 7

Instead, assign variables like this:

 a, b, c, d = 2, 3, 5, 7

Do not use dot operation¶

Because when you call a function using . (dot) it first calls getattribute() or getattr() which then use dictionary operation which costs time. So, try using from module import function.

import math
val = math.sqrt(60)

Rather import at like this:

from math import sqrt
val = sqrt(60)