indexing - Choosing data.table keys in R -

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how choose right keys data.table objects?

are considerations similar rdbmss? first guess have documentation indexes , keys rdbmss. google came helpful stackoverflow question related oracle.

do considerations answer apply data.tables? perhaps exception of relating update, insert or delete type statements? i'm guessing our data.tables objects won't used in way.

i'm trying head around stuff using documentation , examples, haven't seen discussion on key selection.

ps: @crayola pointing me toward data.table package in first place!

i not sure helpful answer, since mention me in question i'll think anyway. remember bit of data.table newbie myself.

i use keys when there clear benefit it, e.g. merging datatables, or seems clear doing speed things (e.g. subsetting repeatedly on variable). knowledge, there no real need define keys @ all; package faster data.frame without keys.


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