Merge some list items in a Python List

Question

Say I have a list like this:

[a, b, c, d, e, f, g]

How do modify that list so that it looks like this?

[a, b, c, def, g]
         


        

Answer 1

That example is pretty vague, but maybe something like this?

items = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
items[3:6] = [''.join(items[3:6])]

It basically does a splice (or assignment to a slice) operation. It removes items 3 to 6 and inserts a new list in their place (in this case a list with one item, which is the concatenation of the three items that were removed.)

For any type of list, you could do this (using the + operator on all items no matter what their type is):

items = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
items[3:6] = [reduce(lambda x, y: x + y, items[3:6])]

This makes use of the reduce function with a lambda function that basically adds the items together using the + operator.