How to replace a value in a data frame in R?

Question

I have data frame with 0 values, i want to convert each zero to a random value between 0.1 and 0.5

      X2     X3     X4     X5
390    0  0.000   0.00   0.00
7433   0 27.839   0.00   0.00
5579   0  0.000 151.95   0.00

to be

      X2     X3     X4     X5
390    0.1  0.200   0.43  0.29
7433   0.3 27.839   0.24   0.30
5579   0.4  0.200 151.95   0.50

Answer 1

Could try

indx <- df == 0L
df[indx] <- runif(sum(indx), 0.1, 0.5)