常见问题汇总

1、一行代码实现99乘法表

print('\n'.join(['\t'.join(["%s%s=%s"%(j,i,ij) for j in range(1,i+1)]) for i in range(1,10)]))

2、进度条

def progress(percent, width=50):
    if percent >= 1:
        percent = 1
    show_str = ("[%%-%ds]" %width)%(int(width*percent)*"#")
    print("\r%s %d%%" %(show_str,int(100*percent)),file=sys.stdout,flush=True,end=" ")


data_size = 10000000
recv_size = 0
while recv_size < data_size:
    time.sleep(0.001)
    recv_size += 1024
    percent = recv_size/data_size
    progress(percent,width=100)

3、完成99乘法表

1 * 1 = 1
2 * 1 = 2 2 * 2 = 4
3 * 1 = 3 3 * 2 = 6 3 * 3 = 9
......
9 * 1 = 9 9 * 2 = 18 9 * 3 = 27 9 * 4 = 36 9 * 5 = 45 9 * 6 = 54 9 * 7 = 63 9 * 8 = 72 9 * 9 = 81

递归的方法:

def bar(n):
    for i in range(1,n+1):
        res = "{} * {} = {}".format(n, i, n * i)
        print(res,end="  ")
    if n < 9:
        n += 1
        print("\n")
        bar(n)
bar(1)

循环

n = 1
while n < 10:
    for i in range(1, n + 1):
        res = "{} * {} = {}".format(n, i, n * i)
        print(res,end="\t")
    n+=1
    print("\t")

4、验证码

import string
import random
def code(n):
    s = ""
    for i in range(n):
        s1 = chr(random.randint(65,90))
        s2 = str(random.randint(0,9))
        s += random.choice([s1,s2])
    return s

# print(string.ascii_letters) #大小写字母
# print(string.digits) #0-9数字

#####################

def code1(n):
    return "".join(random.sample(string.ascii_letters+string.digits,n)) 

print(code1(6))  #这种方式取的值没有重复的

#####################

def code2(n=5):
    s = ""
    for i in range(n):
        s1 = random.choice(string.ascii_letters+string.digits)
        s += s1
    return s
print(code2())