Python 列表索引以查找索引元素的编号（如果元素相同）

Question

Im trying to find the indexed version for multiple items in a list, such as

testarray = ["l","hello","l","l"]

for x in testarray:
    if x == "l":
        print(testarray.index(x))

I want the desired output to be 1, 3, 4 , but what I'm getting is 1,1,1

Answer 1

That's because list.index returns the index of the first occurrence of the element, to fix this, you can loop through the indices and values using enumerate :

testarray = ["l", "hello", "l", "l"]

for i, x in enumerate(testarray, 1):
    if x == "l":
        print(i)

Output:

1
3
4

In for i, x in enumerate(testarray, 1) , i in the index, x is the value, and the second parameter 1 in enumerate tells it to start counting at 1 instead of by default at 0 .