【Python基礎】timeモジュールを使ってプログラムの処理時間を正確に計測する方法

import time

starttime = time.time()

a = []
for i in range(10000000):
    a.append(i)
    
endtime= time.time()

print(starttime)
print(endtime)
print(endtime-starttime)

実行結果
1691322619.6151009
1691322621.2553449
1.6402440071105957

import time

starttime = time.perf_counter()

a = []
for i in range(10000000):
    a.append(i)
    
endtime= time.perf_counter()

print(starttime)
print(endtime)
print(endtime-starttime)

実行結果
252326.557575546
252328.43284663
1.8752710839908104

import time

starttime = time.perf_counter_ns()

a = []
for i in range(10000000):
    a.append(i)
    
endtime= time.perf_counter_ns()

print(starttime)
print(endtime)
print(endtime-starttime)

実行結果
252619341482530
252621156542071
1815059541