python代码小题（4）

#输出等腰三角形

i = 1
while i <= 5:
    print(" "*(5-i),end = "")
    j = 1
    while j <= 2*i-1:
        print("*",end = "")
        j += 1
    print("")
    i += 1

#for循环输出9*9乘法表

for j in range(1,10):
    for i in range(1,j+1):
        print(f"{i}*{j}={i*j}",end = "\t")
    print(" ")

#用户登录系统与检验

num = 0
for i in range(3):
    num += 1
    username = input("请输入用户名：")
    password = input("请输入密码：")
    if username =="admin":
        if password == "888":
            print("登陆成功")
            break
        else:
            print("密码错误")
            print(f"你还有{3-num}次机会")
    else:
        print("用户名错误")
        print(f"你还有{3-num}次机会")
else :
    print("系统锁定")

#for循环输出素数

for i in range(1,101):
    for j in range(2,i+1):
        if i%j == 0:
            if j == i:
                print(i)
            else :
                break

#报数输出(7的倍数and余数是7)

i = eval(input("请输入学生数量="))
count = 0
for j in range(1,i+1):
   if j % 7 == 0 or j % 10 == 7:
      continue
   count += 1
else:
   print(f"报数数量{count}")

#字符串与各种输出

s = "python"
print("{}".format(s))#{}占位输出
print("{:30}".format(s))#占30个字符
print("{:>30}".format(s))#输出在后面
print(f"{s}")#等价于第一个
print(f"{s:30}")#等价于第二个
print(f"{s:>30}")#等价于第三个
print(f"{s:*>30}")#前面填充*符号
print(f"{s:*^30}")#放中间
print(f"{s:*^30.2}")#只取前两位

#输出进度条

n = 10
import time
for i in range(n + 1):
    a,b = "**"* i,".."*(n-i)
    c = (i/n)*100
    #print(f"%{c:^3.0f}[{a}-->{b}]")#普通输出
    print("\r"f"%{c:^3.0f}[{a}-->{b}]",end = "")#在同一行
    time.sleep(0.1)