CODEWITHSUNDEEP
pythonslice
ili
ili

Reputation: 216

Slicing the second last character

I have this string here '[2,3,1,1,]'

Im new to slicing and I only know how to slice from the start and from the end but not somewhere between, not even sure if that is possible.

could someone tell me how I can slice this '[2,3,1,1,]' to this '[2,3,1,1]' So removing the second last character only.

Upvotes: 1

Views: 4556

Answers (4)

cards
cards

Reputation: 5005

Using built-in functions such as str.rstrip

l = '[2,3,1,1,]'

l_new = f"{l.rstrip('],')}]" # it doesn't matter the order!
print(l_new)

or str.rpartition

a, _, b = l.rpartition(',')
l_new = a + b
print(l_new)

you can avoid an explicit slicing. See doc for details.

The 1st approach is universal, hence doesn't produce any side-effects. The 2nd may give rise to side-effects if the final last character is not a ,. If necessary use a check, i.e. str.endswith, to fix it.

Upvotes: 0

Mohamed Darwesh
Mohamed Darwesh

Reputation: 684

You can use this for this one case

txt = "[2,3,1,1,]"
print(f"{txt[:-2]}{txt[-1]}")

Even tho storing lists as string is a bit weird

txt[:-2] will get the characters from 0 index to -2 index

txt[-1] will get the last character which is "]"

then I concatenate both with an f"" string

You can use this if you don't wanna use an f string

print(txt[:-2], txt[-1], sep="")

the "sep" argument is so there won't be space between the two prints

Upvotes: 0

Rahul K P
Rahul K P

Reputation: 16081

If you just want to delete the second last character, your can do like this,

s = "[2,3,1,1,]"

s[:-2] + s[-1]
# '[2,3,1,1]'

s[:-2] -> Will slice the string from 0 to -2 index location (without -2 index)

s[-1] -> Will fetch the last element

s[:-2] + s[-1] -> concatenation of the strigs

Upvotes: 4

ti7
ti7

Reputation: 18930

If you're sure you have that string, slice both characters and add the ] back on!

source_string = "[2,3,1,1,]"
if source_string.endswith(",]"):
    source_string = source_string[:-2] + "]"

However, often lists stored as strings are not very useful - you may really want to convert the whole thing to a collection of numbers (perhaps manually removing the "[]" and splitting by ,, or using ast.literal_eval()), potentially converting it back to a string to display later

>>> source_string = "[2,3,1,1,]"
>>> import ast
>>> my_list = ast.literal_eval(source_string)
>>> my_list
[2, 3, 1, 1]
>>> str(my_list)
'[2, 3, 1, 1]'

Upvotes: 1

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