在R中-通过查找不同值的最大值的规则从列中提取值

Question

i have a 3 x 8 Data Frame, and i need to extract the day (column 3) that matches the highest value (column 1) from the Data Frame.

For example,

1    0.931 2015-03-20    Friday
2   -0.105 2015-03-23    Monday
3   -0.470 2015-03-24   Tuesday
4   -0.149 2015-03-25 Wednesday

the highest value is 0.931, so i need to extract the value Friday.

Thanks.

Answer 1

Say, your dataframe ( df ) has the values in column named V1 then you can find the index of the maximum value in this column with which.max(df$V1) . You say you want the corresponding day for this value, say the days are in column named V2 then your day is df$V2[which.max(df$V1)] .