Question

What is the fastest way to initialize a large array in Python

Answer 1

import time
import numpy as np

start_time = time.time()
lst = [1] * 40000000
print("%s seconds" % (time.time() - start_time))

start_time = time.time()
lst = []
lst = [0 for i in range(40000000)] 
print("%s seconds" % (time.time() - start_time))

start_time = time.time()
arr = np.array([1] * 40000000)
print("%s seconds" % (time.time() - start_time))
 
start_time = time.time()
arr = np.array([1 for i in range(40000000)])
print("%s seconds" % (time.time() - start_time))




 
'''
run:
 
0.19373154640197754 seconds
1.5374398231506348 seconds
2.9260823726654053 seconds
3.9488601684570312 second

'''

 

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