CODEWITHSUNDEEP
pythonpython-3.xstringlistfor-loop
DeveloperLV
DeveloperLV

Reputation: 1781

How to fill a new list while iterating over another list?

Code

#Variables
var1 = ['Warehouse Pencil 1.docx', 'Production Pen 20.docx']

list1 = []
for x in var1:
    splitted = x.split()
    a = [splitted[0] + ' ' + splitted[1]]
    list1.append(a)
    print(list1)

Output

[['Warehouse Pencil']]
[['Warehouse Pencil'], ['Production Pen']]

Goal

I am intending to split the list, grab the 1st and 2nd words for each section, and put them into a new list.

Question

Why is my output giving me a weird output? Where am I going wrong?

Desired Output

My desired output should look like this:

['Warehouse Pencil', 'Production Pen']

Grabbing the 1st and 2nd words and put them into 1 list.

Upvotes: 6

Views: 795

Answers (4)

Plax
Plax

Reputation: 23

list.extend()

Since this keyword hasn't been mentioned in the other answers, you can just extend your list instead of appending it.

var1 = ['Warehouse Pencil 1.docx', 'Production Pen 20.docx']

list1 = []
for x in var1:
    splitted = x.split()
    a = [splitted[0] + ' ' + splitted[1]]
    list1.extend(a)  # Notice the difference here! 
print(list1)

Upvotes: 0

Subham
Subham

Reputation: 411

To get the filename. We can use the following approach.

import pathlib

var1 = ['Warehouse Pencil 1.docx', 'Production Pen 20.docx']
file_name = []

for i in var1:
    p = pathlib.Path(i)
    file_name.append(p.stem)
    
print(file_name)

['Warehouse Pencil 1', 'Production Pen 20']

[Program finished]

Upvotes: 0

Mykola Zotko
Mykola Zotko

Reputation: 17814

You can also use the method str.rfind(sub). It returns the highest index in the string where substring sub (space in your case) is found:

[i[:i.rfind(' ')] for i in var1]
# ['Warehouse Pencil', 'Production Pen']

Alternatively, you can use the method str.rsplit(). It splits the string starting from the right:

[i.rsplit(maxsplit=1)[0] for i in var1]
# ['Warehouse Pencil', 'Production Pen']

Upvotes: 1

CDJB
CDJB

Reputation: 14506

This should fix it - move the print statement out of the loop, and make a a string rather than a list.

#Variables
var1 = ['Warehouse Pencil 1.docx', 'Production Pen 20.docx']

list1 = []
for x in var1:
    splitted = x.split()
    a = splitted[0] + ' ' + splitted[1]
    list1.append(a)
print(list1)

Output:

['Warehouse Pencil', 'Production Pen']

You could also use a list comprehension:

>>> [' '.join(x.split()[:2]) for x in var1]
['Warehouse Pencil', 'Production Pen']

Upvotes: 17

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