How to append multiple items in one line in Python

Question

I have:

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

I wanted to make the newlist.append() statements into a few statements.

Asked By: whatever

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Source

Answer 1

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]

Answered By: Ignacio Vazquez-Abrams

Answer 2

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.

Answered By: Karl Knechtel

Answer 3

You could also:

newlist += mylist[i:i+22]

Answered By: Kevin Postlewaite

Answer 4

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]

Answered By: saoud rehman

Answer 5

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…:)

Answered By: Idrisi_Kasim

Answer 6

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])

Answered By: zakizakibzr

Answer 7

If you are adding the same element then you can do the following:

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

Answered By: Daring_T

How to append multiple items in one line in Python

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