numpy

Posted 2021-01-14 chjh

1、处理日期时间

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import datetime print(datetime.datetime.now()) print("--------------------------------") from datetime import datetime,timedelta now = datetime.now() print(now) print("--------------------------------") dt = datetime(2019,10,22,8,59) print(dt) print("--------------------------------") cday=datetime.strptime(‘2015-6-1 18:19:59‘,‘%Y-%m-%d %H:%M:%S‘) print(cday) print("--------------------------------") now1 =now.strftime(‘%a, %b %d %H:%M‘) print(now1) print("--------------------------------") print(‘今天是{0:%y}年的第{0:%j}天。‘.format(now)) print("--------------------------------") print(dt-now) print("--------------------------------")

 

2.

数列：a = a1,a2,a3,·····,an  ;    b = b1,b2,b3,·····,bn

求：c = a12+b13,a22+b23,a32+b33,·····+an2+bn3

 

import numpy as py

from datetime import datetime

 

def listSum(n):

    a=list(range(n))

    b=list(range(0,5*n,5))

    c=[]

    for i in range(len(a)):

     c.append(a[i]**2+b[i]**3)

    return c

 

 

def numpySum(n):

    a=py.arange(n)

    b=py.arange(0,5*n,5)

    c=a**2+b**3

    return c

 

now1=datetime.now()

print(listSum(1000000))

now2=datetime.now()

print(now2-now1)

 

 

now3=datetime.now()

print(numpySum(1000000))

now4=datetime.now()

print(now4-now3)