I have one data frame which has one column & two records in it.
DF1=
Name
M_D
ABC123
I have another dataframe which has two columns. I need to rename second dataframe columns with two values in first data frame.
DF2=
PQR LMN
111 345
456 999
I want DF2 as below
M_D ABC123
111 345
456 999
Thanks
You can access values for column names for DF2 using $ or [[ operator on DF1. Since OP has mentioned that he doesn't even know the column names of DF1, an option could be as:
names(DF2) <- DF1[,1]
DF2
# M_D ABC123
#1 111 345
#2 456 999
#OR
names(DF2) <- DF1[[1]]
#OR
names(DF2) <- DF1$Name
Note: names(DF2) <- DF1[1] will not work as DF1[1] is still of type data.frame and names<- expects a vector.
Data:
DF2 <- read.table(text =
"PQR LMN
111 345
456 999",
header = TRUE, stringsAsFactors = FALSE)
DF1 <- read.table(text =
"Name
M_D
ABC123",
header = TRUE, stringsAsFactors = FALSE)
Based on your comment above, I recommend hardcoding it with something like dplyr::rename().
DF2 <- DF2 %>%
dplyr::rename(
M_D = PQR,
ABC123 = LMN
)
In my experience, you shouldn't really trust that collaborators will give you the same dataset structure each time. This will throw an error if they've changed the column names (this is good --you want to be alerted to the problem early in the pipeline). If they've change the column order, dplyr::rename() will handle it gracefully & correctly.
Consider additional defensive programming tools like checkmate or testit to verify the column characteristics match your expectations (e.g., the PQR/M_D column is an integer with values between 0 and 5).
This will work if the length of DF1$Name is the same as the number of columns of DF2
colnames(DF2) <- DF1$Name