Comprehension Performance
List comprehensions are faster than equivalent for-loops because they are optimized in CPython. Generator expressions save memory but are slower per element if you need a list anyway.
Python
Intermediate
4 min read
Comprehension Performance
Example
import timeit
list_comp = timeit.timeit("[x**2 for x in range(1000)]", number=10000)
gen_exp = timeit.timeit("list(x**2 for x in range(1000))", number=10000)
print(f"List: {list_comp:.2f}s Gen: {gen_exp:.2f}s") Pro Tip
Profile before optimizing — readability matters more than micro-optimizations.