Demo entry 6838925

test

   

Submitted by anonymous on Jun 12, 2019 at 10:42
Language: RConsole. Code size: 132 Bytes.

try <- data[data$cola == 'a' & data$colb == 'b']#需要跑遍所有的数据,非常的费时

setkey(data, cola, colb)#数据已经完成排序
try <- DT[list('a','b')]#非常快!

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