Merge the first elements in a list a tuples if the second elements are the same?

Question

I have a list of tuples:

[('Donald', 'PERSON'), ('Trump', 'PERSON'), ('enters', 'O'), ('the', 'O'), ('White', 'LOCATION'), ('House', 'LOCATION')]

and the output I want is:

[('Donald Trump'), ('enters the'), ('White House')]

The below code gets me closer to the wanted result, but I'm not really familiar with the groupby function yet.

mergedTags = []
    from itertools import groupby
    for tag, chunk in groupby(tagList, lambda x: x[1]):
        if tag != "O":
            tagMerged = " ".join(w for w, t in chunk)
            mergedTags.extend([tagMerged])
        else:
            #tagMerged = " ".join(t for t, w in chunk)
            for word, chunk in groupby(tagList, lambda x: x[0]):
                mergedTags.extend([word])

    print(mergedTags)

Answer 1

You may use itertools.groupby with list comprehension expression as:

from itertools import groupby
my_list = [('Donald', 'PERSON'), ('Trump', 'PERSON'), ('enters', 'O'), ('the', 'O'), ('White', 'LOCATION'), ('House', 'LOCATION')]

output_list = [tuple(i[0] for i in e) for _, e in groupby(my_list, lambda x: x[1])]
#                 ^ generate the desired tuple

where the value hold by output_list will be:

[('Donald', 'Trump'), ('enters', 'the'), ('White', 'House')]