Hi all,
Imagine I have a matrix and the first colum is a list that repeats the same
names, I want to sum the second column on each unique name on first column.
Imagine this:
Pepe 2
Pepe 3
Pepe 4
Jose 2
Jose 5
Manuel 4
Manuel 2
I want to make a new matrix that calculates and recognizes that there are 3
different names ans sum second column. But a priori I don´t know the list of
the different names:
In my example
Pepe 9
Jose 7
Manuel 6
I´m trying to use something like sapply or apply but I can find the key...
Can anyone help or guide me ?
Thanks in advance¡¡¡
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