CODEWITHSUNDEEP
rdataframedata-cleaning
MiRe Y.
MiRe Y.

Reputation: 57

R How to delete a column if column values equal to the column name

I have a data set that contains a bunch of columns where the column values(all values of that column) is exactly the same as that column name. How can I delete that column. I cannot delete the columns one by one as there are over 700 variables. Thanks!

Upvotes: 0

Views: 493

Answers (3)

ThatGuy
ThatGuy

Reputation: 1233

Does this help?

data = data.frame(name1=rep("name1",5), name2=rep("name2",5), name3=rep("name3",5), name4=rep("name4",5)) #Some test data

ColsToRemove <- names(data)[which(sapply(data[1,], function(x){x %in% names(data)}))] #Finds where the column name is the same as the first entry and marks it for deletion

cleanData = data[ , !(names(data) %in% ColsToRemove)] #This deletes the columns named

head(data)
head(cleanData)

Upvotes: 1

Onyambu
Onyambu

Reputation: 79208

You can use sweep to determine all the values that are not equal to the colnames 

data[colSums(sweep(data,2,colnames(data),"!="))>0]

Upvotes: 0

Alejandro Andrade
Alejandro Andrade

Reputation: 2216

Here is an example of how you could do it:

data = data.frame(x1 = rep(1,10), x2 = seq(1,20,by = 2),
                  x3 = rep("x3",10), x4 = 1:10, x5 = rep("x5",10))

col_rm = which(sapply(1:ncol(data), function(x) all(data[,x] == colnames(data)[x])))
data = data[,-col_rm]

basically what the code does it that finds if all the values of the column x are equal to the name of the column and finds all the columns that fulfill that condition and then i just remove them with -.

Upvotes: 3

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