跟踪循环 Python，为什么输出是 90？

Question

我正在跟踪代码中的循环。谁能帮我追踪代码并帮助我理解为什么输出是 90？

m = 4
n = 5
x = 0
for i in range(1,m):
       x = x + i + 10            //x inside i loop
       for j in range(1,n):
            x = x + i + j        //x inside j loop
print(x)

Answer 1

跟踪循环很简单，只需在里面添加打印语句（这里首先使用 i 迭代 1 到 4 然后将 i+10 添加到 x 然后再次将 j 迭代 1 到 5 并添加 i+ j 到 x)

m = 4
n = 5
x = 0
for i in range(1,m):
       x = x + i + 10
       print(x)
       
       for j in range(1,n):
            x = x + i + j
            print(x, end = " ")
       print()
       print()

print(x)

在运行下面的代码之后你会看到下面的输出

11                                                                                                                                                                                                     
13 16 20 25                                                                                                                                                                                            
                                                                                                                                                                                                       
37                                                                                                                                                                                                     
40 44 49 55                                                                                                                                                                                            
                                                                                                                                                                                                       
68                                                                                                                                                                                                     
72 77 83 90                                                                                                                                                                                            
                                                                                                                                                                                                       
90

Answer 2

如果你想要循环的每一个进度。

代码：

m = 4
n = 5
x = 0
for i in range(1,m):
    print("Outer Loop: {}+{}+10".format(x, i))
    x = x + i + 10
    print("Outer Sum x=",x)
    for j in range(1,n):
        print("\tInner Loop: {}+{}+{}".format(x, i, j))
        x = x + i + j
        print("\tInner Sum =", x)
print("Total =",x)

输出：

Outer Loop: 0+1+10
Outer Sum x= 11
    Inner Loop: 11+1+1
    Inner Sum = 13
    Inner Loop: 13+1+2
    Inner Sum = 16
    Inner Loop: 16+1+3
    Inner Sum = 20
    Inner Loop: 20+1+4
    Inner Sum = 25
Outer Loop: 25+2+10
Outer Sum x= 37
    Inner Loop: 37+2+1
    Inner Sum = 40
    Inner Loop: 40+2+2
    Inner Sum = 44
    Inner Loop: 44+2+3
    Inner Sum = 49
    Inner Loop: 49+2+4
    Inner Sum = 55
Outer Loop: 55+3+10
Outer Sum x= 68
    Inner Loop: 68+3+1
    Inner Sum = 72
    Inner Loop: 72+3+2
    Inner Sum = 77
    Inner Loop: 77+3+3
    Inner Sum = 83
    Inner Loop: 83+3+4
    Inner Sum = 90
Total = 90

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