在 Python 中如何在一行中追加多个项

我有:

count = 0
i = 0
while count < len(mylist):
if mylist[i + 1] == mylist[i + 13] and mylist[i + 2] == mylist[i + 14]:
print mylist[i + 1], mylist[i + 2]
newlist.append(mylist[i + 1])
newlist.append(mylist[i + 2])
newlist.append(mylist[i + 7])
newlist.append(mylist[i + 8])
newlist.append(mylist[i + 9])
newlist.append(mylist[i + 10])
newlist.append(mylist[i + 13])
newlist.append(mylist[i + 14])
newlist.append(mylist[i + 19])
newlist.append(mylist[i + 20])
newlist.append(mylist[i + 21])
newlist.append(mylist[i + 22])
count = count + 1
i = i + 12

我想把 newlist.append()语句分成几个语句。

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最佳答案

No. The method for appending an entire sequence is list.extend().

>>> L = [1, 2]
>>> L.extend((3, 4, 5))
>>> L
[1, 2, 3, 4, 5]
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No.

First off, append is a function, so you can't write append[i+1:i+4] because you're trying to get a slice of a thing that isn't a sequence. (You can't get an element of it, either: append[i+1] is wrong for the same reason.) When you call a function, the argument goes in parentheses, i.e. the round ones: ().

Second, what you're trying to do is "take a sequence, and put every element in it at the end of this other sequence, in the original order". That's spelled extend. append is "take this thing, and put it at the end of the list, as a single item, even if it's also a list". (Recall that a list is a kind of sequence.)

But then, you need to be aware that i+1:i+4 is a special construct that appears only inside square brackets (to get a slice from a sequence) and braces (to create a dict object). You cannot pass it to a function. So you can't extend with that. You need to make a sequence of those values, and the natural way to do this is with the range function.

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You could also:

newlist += mylist[i:i+22]
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mylist = [1,2,3]


def multiple_appends(listname, *element):
listname.extend(element)


multiple_appends(mylist, 4, 5, "string", False)
print(mylist)

OUTPUT: 

[1, 2, 3, 4, 5, 'string', False]
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Use this :

#Inputs
L1 = [1, 2]
L2 = [3,4,5]


#Code
L1+L2


#Output
[1, 2, 3, 4, 5]

By using the (+) operator you can skip the multiple append & extend operators in just one line of code and this is valid for more then two of lists by L1+L2+L3+L4.......etc.

Happy Learning...:)

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Use a for loop, it might look like this:

for x in [1,2,7,8,9,10,13,14,19,20,21,22]:
new_list.append(my_list[i + x])
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If you are adding the same element then you can do the following:

["a"]*2
>>> ['a', 'a']

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