r - First element in a data.table aggregation -


i have data.table of tick data, want aggregate seconds timeframe. while getting max, min , last pretty straightforward:

data[, list(max(value), min(value), last(value)), by=time]

i struggling first datapoint corresponds second timestamp. there nothing in manual. there easy way it, say, sql top?

i managed find solution. query first element subset column's first value using [:

data[, list(value[1], max(value), min(value), last(value)),by=time]

maybe helps someone.


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