Deleting duplicates in tuples

[Den]

I have a list of tuples, and I am trying to delete some tuples of the list based on their first element: if the first element is the same first element of the next tuple, then the second tuple, which contains that same first element, should be deleted. I tried doing it through an iterative loop, but it doesn't completely work. Some duplicates are still left in the list.

 for tuple in list:
         index_of_the_first_tuple=list.index(tuple)
         if tuple[0] in list[index_of_the_first_tuple+1]:
             list.pop(index_of_the_first_tuple+1)  
     

[Gribouillis]

then the second tuple, which contains that same first element, should be deleted.

What about the third tuple containing the same first element. Does it need to be deleted too?

[ichabod801]

You shouldn't use the names of Python built-ins (like tuple and list) for you variable names, because then you lose access to the built-ins. You should also avoid modifying a list that you are iterating over. That's probably why your program is failing. You should build a new list without the items you want to remove:

new_data = data[:1]
for item in data[1:]:
    if item[0] != new_data[-1][0]:
        new_data.append(item)
data = new_data

Note that this will delete the third and succeeding duplicates taht Gribouillis mentioned. Also, if the list is not sorted, it will not remove all of the duplicates.