python第三章课后练习题

3.19
import time
date_str = time.strftime("%Y年%m月%d日",time.localtime())
print("当前日期：",date_str)

3.20
import time
current_time = time.localtime()
format1 = time.strftime("%Y年%m月%d日",current_time)
print("格式1：",format1)
format2 = time.strftime("%Y-%m-%d",current_time)
print("格式2：",format2)
format3 = time.strftime("%Y/%m/%d %H:%M:%S",current_time)
print("格式1：",format3)
format4 = time.strftime("%b %d, %Y",current_time)
print("格式1：",format4)
format5 = time.strftime("%A,%B %d,%Y",current_time)
print("格式1：",format5)

3.21
from tqdm import tqdm
import time
start_time = time.time()
scale = 10
print("------执行开始------")
for i in range(scale + 1):
a,b = '**' * i,'..'(scale-i)
c = (i/scale)100
elapsed_time = time.time() - start_time
print("%{:>3.0f}[{}->{}]{:.2f}".format(c,a,b,elapsed_time))
time.sleep(0.1)
print("------执行结束------")

3.6
import time
print("Starting",end='')
a='...'
print("{:^5}".format(a),end='')
print("Done!")

3.7
while True:
for i in ["/","-","|","\","|"]:
print("%s\r" % i)

3.8

tqdmBar.py

from tqdm import tqdm
from time import sleep
for i in tqdm(range(1,100)):
sleep(0.01)