Is there a R function to delete an element in data frame

December 22, 2021

I’m looking for a way to delete an element out of a data frame (delete the full row) if a certain word is not found in the Name column. In my case, the element is a color like red,blue,green

The dataset looks like this:

Name|Classification
A red apple | Fruit
A banana | Fruit
A blue carrot | Vegetable

I use the following code to loop through the dataframe and check if a color is in the string of Name column. Currently only looking at red to make it work.

for(i in 1:length(nsl)){
if(!grepl("red",nsl[[1:i]],fixed=TRUE)){
nsl[[1:i]] <- " " #This is where I want to delete the item or set it to empty (so later on I can filter all empty out)
}
}

But I have no clue how it is done on a data frame that has two columns/dimensions. All internet tutorials I find tell me to use nsl[-index_element_here] but that deletes the column Classification. Which they use on examples of 1-D lists. Or tell me to use %in% which is , I think, not what I’m looking for.

The expected end result is a dataframe where only fruit and vegetables with color are in. Non-colour is deleted.

>Solution :

There is no need for a loop:

nsl <- read.table(text = "Name|Classification
'A red apple' | Fruit
'A banana' | Fruit
'A blue carrot' | Vegetable
", header = TRUE, sep = "|")

nsl[!grepl("red", nsl$Name, fixed = TRUE), ]
#>             Name Classification
#> 2      A banana           Fruit
#> 3 A blue carrot       Vegetable