r change column value conditionally

To change column values conditionally in R, you can use the ifelse() function. This function allows you to specify a condition and provide values for when the condition is TRUE or FALSE. Here is an example of how to use ifelse() to change column values conditionally:

# Create a data frame
df <- data.frame(A = c(1, 2, 3, 4, 5),
                 B = c(6, 7, 8, 9, 10))

# Change values in column B based on a condition
df$B <- ifelse(df$A > 3, "High", "Low")

In this example, we first create a data frame df with two columns, A and B. The column A contains the values 1, 2, 3, 4, and 5, while column B initially contains the values 6, 7, 8, 9, and 10.

We then use the ifelse() function to change the values in column B based on a condition. The condition we specify is df$A > 3, which checks if the values in column A are greater than 3. If the condition is TRUE, the corresponding value in column B is set to "High". If the condition is FALSE, the corresponding value in column B is set to "Low".

After executing the code, the values in column B will be changed based on the condition. The resulting data frame will look like this:

  A     B
1 1   Low
2 2   Low
3 3   Low
4 4  High
5 5  High

By using the ifelse() function, you can easily change column values conditionally in R based on specific criteria or conditions.