我正在写一个带有if语句的for循环，但它什么都不返回？

问题描述

我试图查找两个不同数组中是否存在共享元素，我编写了以下代码，但未返回任何内容。

    gradelist1 = [1,3,5]
    gradelist2 = [1,4,7]
    for value in (gradelist1,gradelist2):
        if value in gradelist1 and value in gradelist2:
            print('The value occurs in both the lists')
            break

解决方法

您要遍历列表，而不是遍历列表中的值。同样，也不需要一次遍历两个列表。

gradelist1 = [1,3,5]
gradelist2 = [1,4,7]
for value in gradelist1:
   if value in gradelist2:
        print('The value occurs in both the lists')
        break

您也可以只进行列表理解[i for i in gradelist1 if i in gradelist2]来直接获取两个列表中的所有值。

,

以这种方式做

gradelist1 = [1,7]
x = [] # create a list
for value in (gradelist1):
    if value in gradelist2: #first check if the value from the list1 is in the list 2
      x.append(value) # add to it the values if the condition is rigth

print('the folloging numbers are inclued in both arrays')
print(x)

,

您的代码应如下所示：

 gradelist1 = [1,5]
 gradelist2 = [1,7]
 for value1,value2 in zip(gradelist1,gradelist2):
        if value1 in gradelist1 and value2 in gradelist2:
            print('The value occurs in both the lists')
            break