CODEWITHSUNDEEP
rmin
lagn91
lagn91

Reputation: 77

min(which()) not retrieving the correct number under condition

I have a 4 x 600 datatable with 3 numeric columns with random integers ranging from 0 - 700. I have defined a variable as an integer with a value of 542. I am attempting to identify the minimum value that is greater than 542 in each of the numeric columns. However, the following works but is pulling the wrong value, any idea why? Or if I am doing something wrong?

#data.table called df with numeric columns being b,c,d

a <- as.integer(542)
min(which(df$b > a))
[1] 131

How is that possible? I know the correct value should be 543 for this column.

Upvotes: 1

Views: 56

Answers (2)

ThomasIsCoding
ThomasIsCoding

Reputation: 101628

You should know that which.min is equivalent to

which(x == min(x, na.rm = TRUE))

and it is definitely different from min(which(x))

Upvotes: 1

akrun
akrun

Reputation: 887153

The output from which is a position index and the the min applied on which returns the minimum position and not the position of minimum value. Use the output from which to extract the values in 'b' and then wrap with min

min(df$b[which(df$b > a)])

Upvotes: 1

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