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  • python之for循环

    for循环,也称定循环,即一般用于循环次数确定的循环,通常可用于遍历序列,如字符串str,列表list,元组tuple等

    格式:

    for 变量 in 序列:

      command1

      command2

      ...

    示例1.for与range的合用

    range函数可用于产生一个数字序列,

    (1).range(n)

    只传一个数字给range时,会产生一个从0到n-1的数字序列

    for i in range(5):
        print(i, end=" ")
    print()

    输出结果如下:
    0 1 2 3 4 

    (2)range(n, m)

    传两个参数给range,会产生从n到m-1的数字序列

    for i in range(3, 10):
        print(i,end=" ")
    print()
    
    输出结果如下:
    3 4 5 6 7 8 9 

    (3)range(n, m, k)

    传三个参数给range,会产生n,n+k,n+2k,......,最后一个数小于m

    for i in range(1, 20, 2):
        print(i, end=" ")
    print()
    
    输出结果如下:
    1 3 5 7 9 11 13 15 17 19 

    示例2:九九乘法表

    for i in range(1, 10):
        for j in range(1, i+1):
            print("%d * %d = %d	" % (j, i, i*j), end="")
        print()

    输出结果如下

    1 * 1 = 1
    1 * 2 = 2 2 * 2 = 4
    1 * 3 = 3 2 * 3 = 6 3 * 3 = 9
    1 * 4 = 4 2 * 4 = 8 3 * 4 = 12 4 * 4 = 16
    1 * 5 = 5 2 * 5 = 10 3 * 5 = 15 4 * 5 = 20 5 * 5 = 25
    1 * 6 = 6 2 * 6 = 12 3 * 6 = 18 4 * 6 = 24 5 * 6 = 30 6 * 6 = 36
    1 * 7 = 7 2 * 7 = 14 3 * 7 = 21 4 * 7 = 28 5 * 7 = 35 6 * 7 = 42 7 * 7 = 49
    1 * 8 = 8 2 * 8 = 16 3 * 8 = 24 4 * 8 = 32 5 * 8 = 40 6 * 8 = 48 7 * 8 = 56 8 * 8 = 64
    1 * 9 = 9 2 * 9 = 18 3 * 9 = 27 4 * 9 = 36 5 * 9 = 45 6 * 9 = 54 7 * 9 = 63 8 * 9 = 72 9 * 9 = 81

    示例三:打印倒三角形

    for i in range(1, 6):
        for j in range(6-i, 0, -1):
            print("*", end=" ")
        print()
    
    输出结果如下
    * * * * * 
    * * * * 
    * * * 
    * * 
    * 
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  • 原文地址:https://www.cnblogs.com/golinux/p/10770836.html
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