Hello,
I am a beginner with Mathematica.
I work with a dataset of logs containing user/itemid/rating.
I try to extract logs for which the rating are up to a value.
Herafter my attempt:
In[10]:= DataSetOutTime[[1]]
Out[10]= {196, 242, 3}
In[20]:= Select[DataSetOutTime, DataSetOutTime[[All, 3]] > 3 &]
Out[20]= {}
Is there something easy like (possible with python) “Extract= [x for x in DataSetOutTime if DataSetOutTime[x,3] > 3]” ?
BR
There’s a syntax kinda like this with Dataset. Dataset is kinda like Dataframes from Python’s Pandas package.
To do it simply however, I would just write the following.
Select[DataSetOutTime, #[[3]] > 3 &]
or maybe
Select[DataSetOutTime, Last[#] > 3 &]
This says “Select every element from DataSetOutTime where the third/last element of element is greater than three”.
Thks a lot: your propositions are OK !
Now, I’d like to extract from the previous set (logs with ratings up to 3), the logs attached to a user who has performed at least 10 ratings (I will compute accuracy and recall and wish to work with user with at least 10 rates).
In others words, I retain userid only if the userid appears at least 10 times.
I can select this list of userid:
In[196]:= TableUserIDAuMoins10 =
Select[Counts[CorpusReferenceu1test[[All, 1]]], # > 9 &]
Out[196]= <|1 → 79, 2 → 12, 5 → 25, 6 → 64, 7 → 135, 8 → 22,
…|>
In[197]:= Keys[TableUserIDAuMoins10]
Out[197]= {1, 2, 5, 6, 7, 8, 10, 11, 12, 13, …}
But now, I don’t see how I can write "select logs form CorpusReferenceu1test where userid is within Key[TAbleUSerIDAumoins10]…
(logs are (userid, itemid, rates), so that Keys[TableUserIDAuMoins10] can be seen as the list of the available userid )
BR