尝试分配循环索引时,'int'对象不可迭代

Question

这真的很奇怪,请在下面的代码片段中循环,当我删除时num=i,一切正常,但有了它,它导致迭代问题.

错误代码

In [17]: prim_list=[]
    ...: for i in range(2,101):
    ...:     print i
    ...:     num=i,count=0        # line with issue
    ...:     for j in range(1,i/2):
    ...:         div=j
    ...:         if(num%div==0):
    ...:             count=count+1
    ...:     if(count==1):
    ...:         prim_list.append(num)
    ...:
2
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-17-a8dd2a52322e> in <module>()
      2 for i in range(2,101):
      3     print i
----> 4     num=i,count=0
      5     for j in range(1,i/2):
      6         div=j

TypeError: 'int' object is not iterable

工作正常

In [19]: prim_list=[]
    ...: for i in range(2,101):
    ...:     count=0              # notice num=i assignment is removed
    ...:     for j in range(1,i/2):
    ...:         div=j
    ...:         if(num%div==0):
    ...:             count=count+1
    ...:     if(count==1):
    ...:         prim_list.append(num)
    ...: print "done"
    ...:
done

我不理解的是为什么赋值导致循环迭代错误!! ??

任何帮助表示赞赏!

Answer 1

您正在使用链式作业:

num=i,count=0

是

num = (i, count) = 0

在哪里num = 0和(i, count) = 0被分配.因为0它不是长度为2的可迭代,所以它不能分配给目标元组.

使用

num, count = i, 0

要么

num = i
count = 0

代替.