adding first part to input()

[Eric Smith]

How do I add a string so that it occurs at the prompt which is spaned
by the input() command? I could potentially delete all or part of this
string or just start typing after it.

My prompt might look like:

Enter item to search for:   set_
                                             ^
                                            cursor

The "set_" will be added to whatever I type at the cursor.

Thanks

--
Eric Smith