Is there a way to replace only the first zero in a column in R-CodePudding

So I have a data frame that looks like

df
1
1
1
1
1
1
0
0
0

Is there a way to change just the first zero, the one in row 7, to a different value I have stored in my environment. In this exact case it's the value is stored under

new <- .4

The first 0 is in a different place for each dataset I have, some are dozens of rows long.

CodePudding user response：

There should be multiple ways to do this.

Here is an option with match -

data <- data.frame(num = rep(c(1, 0), c(6, 3)))
new <- .4
data$num[match(0, data$num)] <- new
data

#  num
#1 1.0
#2 1.0
#3 1.0
#4 1.0
#5 1.0
#6 1.0
#7 0.4
#8 0.0
#9 0.0

match would return index of 1st matching value.

CodePudding user response：

For replacing a single value at a specific location you can use

df["Row number", "Column number"] = "New value"

In your case that would be:

df[7,1] = 0.4

or for the stored variable: df[7,1] = new