在二维矩阵中查找值的索引

问题描述：

我有一个形式的矩阵，

mymatrix=[[1,2,3],[4,5,6],[7,8,9]]

我想获取例如位于(2,2)处的9的索引.

I want to the get the index of, say for example, 9 which is at (2,2).

到目前为止我一直在尝试做的事情.

What I have tried to do so far.

for i,j in enumerate(mymatrix):
   for k,l in enumerate(j):
     if l==9:
         print i,k

有没有更好的方法可以做到这一点.优化，有人吗?预先感谢.

Is there a better way of doing the same. Optimization, anyone? Thanks in advance.

答

如果希望该值出现的所有位置，则可以使用以下列表推导，将val设置为要搜索的内容

If you want all of the locations that the value appears at, you can use the following list comprehension with val set to whatever you're searching for

[(index, row.index(val)) for index, row in enumerate(mymatrix) if val in row]

例如:

>>> mymatrix=[[1,2,9],[4,9,6],[7,8,9]]
>>> val = 9
>>> [(index, row.index(val)) for index, row in enumerate(mymatrix) if val in row]
[(0, 2), (1, 1), (2, 2)]

编辑

这并不是真的，因为它只会出现所有出现的值，只会在给定的行中第一次出现该值.

It's not really true that this gets all occurrences, it will only get the first occurrence of the value in a given row.

在二维矩阵中查找值的索引

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