Python 如何从列表中删除第一个项目？
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How to remove the first Item from a list?
提问by rectangletangle
I have the list [0, 1, 2, 3, 4]I'd like to make it into [1, 2, 3, 4]. How do I go about this?
我有[0, 1, 2, 3, 4]我想加入的清单[1, 2, 3, 4]。我该怎么做？
采纳答案by kevpie
list.pop(index)
list.pop（索引）
>>> l = ['a', 'b', 'c', 'd']
>>> l.pop(0)
'a'
>>> l
['b', 'c', 'd']
>>>
del list[index]
删除列表[索引]
>>> l = ['a', 'b', 'c', 'd']
>>> del l[0]
>>> l
['b', 'c', 'd']
>>>
These both modify your original list.
这些都修改了您的原始列表。
Others have suggested using slicing:
其他人建议使用切片：
- Copies the list
- Can return a subset
- 复制列表
- 可以返回一个子集
Also, if you are performing many pop(0), you should look at collections.deque
此外，如果您正在执行许多 pop(0)，您应该查看collections.deque
from collections import deque
>>> l = deque(['a', 'b', 'c', 'd'])
>>> l.popleft()
'a'
>>> l
deque(['b', 'c', 'd'])
- Provides higher performance popping from left end of the list
- 提供从列表左端弹出的更高性能
回答by justin.m.chase
Slicing:
切片：
x = [0,1,2,3,4]
x = x[1:]
Which would actually return a subset of the original but not modify it.
这实际上会返回原始的子集但不会修改它。
回答by Haes
回答by Zimm3r
you would just do this
你会这样做
l = [0, 1, 2, 3, 4]
l.pop(0)
or l = l[1:]
或者 l = l[1:]
Pros and Cons
利弊
Using pop you can retrieve the value
使用 pop 你可以检索值
say x = l.pop(0)xwould be 0
说x = l.pop(0)x会0
回答by martineau
Then just delete it:
然后删除它：
x = [0, 1, 2, 3, 4]
del x[0]
print x
# [1, 2, 3, 4]
回答by vertexion
You can also use list.remove(a[0])to popout the first element in the list.
您还可以使用list.remove(a[0])到pop了第一个元素在列表中。
>>>> a=[1,2,3,4,5]
>>>> a.remove(a[0])
>>>> print a
>>>> [2,3,4,5]
回答by Yoni Shperling
You can use list.reverse()to reverse the list, then list.pop()to remove the last element, for example:
您可以使用list.reverse()反转列表，然后list.pop()删除最后一个元素，例如：
l = [0, 1, 2, 3, 4]
l.reverse()
print l
[4, 3, 2, 1, 0]
l.pop()
0
l.pop()
1
l.pop()
2
l.pop()
3
l.pop()
4
回答by tsveti_iko
回答by Bhaskar Bhuyan
There is a datastructure called "deque" or double ended queue which is faster and efficient than a list. You can use your list and convert it to deque and do the required transformations in it. You can also convert the deque back to list.
有一种称为“deque”或双端队列的数据结构，它比列表更快、更高效。您可以使用您的列表并将其转换为双端队列并在其中执行所需的转换。您还可以将双端队列转换回列表。
import collections
mylist = [0, 1, 2, 3, 4]
#make a deque from your list
de = collections.deque(mylist)
#you can remove from a deque from either left side or right side
de.popleft()
print(de)
#you can covert the deque back to list
mylist = list(de)
print(mylist)
Deque also provides very useful functions like inserting elements to either side of the list or to any specific index. You can also rotate or reverse a deque. Give it a try!!
Deque 还提供了非常有用的功能，例如将元素插入到列表的任一侧或任何特定索引。您还可以旋转或反转双端队列。试一试！！
