How to subtract two strings?

Question

I have a long string, which is basically a list like str=\"lamp, bag, mirror,\" (and other items)

I was wondering if I can add or subtract some items, i

Answer 1

You can do this as long as you use well-formed lists:

s0 = "lamp, bag, mirror"
s = s0.split(", ") # s is a list: ["lamp", "bag", "mirror"]

If the list is not well-formed, you can do as follows, as suggested by @Lattyware:

s = [item.strip() for item in s0.split(',')]

Now to delete the element:

s.remove("bag")
s
=> ["lamp", "mirror"]

Either way - to reconstruct the string, use join():

", ".join(s)
=> "lamp, mirror"

A different approach would be to use replace() - but be careful with the string you want to replace, for example "mirror" doesn't have a trailing , at the end.

s0 = "lamp, bag, mirror"
s0.replace("bag, ", "")
=> "lamp, mirror"