Multi tool use

How to extract rows from my data frame without having a data format conversion?

I would like to extract rows from a big dataset, named data1.
My destination is to add a new column next to the Value of the extracted data1.
Before that, I need to extract some GeneSymbols and then I would like to make a new column in the extracted data frame.

Let's hypothetically say if this is my data.

GeneSymbol ID Value
let-7 A 0.5
miR-16 A 0.7
miR-19 A 0.3
miR-21 A 0.2

add1 = 1
data11 = cbind(data1, add1)
head(data11)
GeneSymbol ID Value add1
let-7 A 0.5 1
miR-16 A 0.7 1
miR-19 A 0.3 1
miR-21 A 0.2 1


It works well if I do not extract rows from my data set.
However, I am in trouble if I do like this.

newdata1 = data1[c("let-7", "miR-19"),]
head(newdata1)
GeneSymbol ID Value
<NA> <NA> NA
<NA> <NA> NA


Why my data became NAs?
I got stuck.
Since my real data is big, over 30,000 rows.
Also, my target rows of interest locate randomly, so I definitely want to sort by GeneSymbol, not a row's number.

1 Answer
1

We can use %in% to get a logical vector for subsetting the rows

%in%

data1[data1$GeneSymbol %in% c("let-7", "miR-19"),]
# GeneSymbol ID Value
#1 let-7 A 0.5
#3 miR-19 A 0.3


The "let-7", "miR-19" are elements in the 'GeneSymbol` and it is not row.names. So, using that in the row index get NA rows as those are in the original dataset

"let-7", "miR-19"

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