r - Determine the max values in one column based on another column -

i determine max values in column value1 based values in column value2:

df <- 'inf value1 value2        xx1   20    30        xx2   15    40        xx3   25    20' df <- read.table(text=df, header=t) 

my expected output that:

out <- 'inf value1 value2        xx1   20    30        xx2   15    40        xx3   20    20' out <- read.table(text=out, header=t) 

in third row in column value2 have 20 instead 25, because value @ value2column @ same row. have large dataset, appreciate ideas deal that.

you find min value per row using pmin

with(df, pmin(value1, value2)) ## [1] 20 15 20 

---

some benchmarks

set.seed(123) test1 <- sample(1e3, 1e8, replace = true) test2 <- sample(1e3, 1e8, replace = true)  ### solution system.time(res1 <- pmin(test1, test2))  # user  system elapsed  # 2.87    0.11    3.00   ### @avinash system.time(res2 <- ifelse(test1 < test2, test1, test2)) # user  system elapsed  # 16.33    2.41   18.87   ### contributed @colonel system.time({temp <- test1 > test2 ; test1[temp] <- test2[temp]})  # user  system elapsed  # 2.34    0.29    2.63   identical(res1, res2) # [1] true identical(res1, test1) # [1] true