**20**wrote:

Hi i am carrying out differential gene expression analysis using limma further i need to do gene set enrichment analysis using GOstats but thers a problem. These are my set of differential expressed genes

```
[1] "1557994_at" "205933_at" "1559688_at"
[4] "232837_at" "212253_x_at" "212845_at"
[7] "233520_s_at" "236931_at" "205054_at"
[10] "237981_at" "209896_s_at" "221718_s_at"
[13] "226648_at" "208195_at" "211928_at"
```

but when I convert the character vector to numeric I get a warning that NA's introduced as coercion and getting result somewhat this way :

```
[1] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
[26] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
[51] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
[76] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
```

how do I solve this problem. And when i carry out analysis its taking hours and no output .

**92k**• written 5.7 years ago by shaikhfarahdeeba •

**20**

Are you literally just

`as.numeric(d)`

on a character vector`d`

(just as an example)? That will always produce an NA since there's no obvious conversion between probe IDs like that and numbers. You can`as.numeric(c("1","2","100"))`

since those are just character representations of numbers, but you have probe IDs.92kis it necessary to convert them into numeric vecctor

20Have you read the GOstats documentation (PDF) ? Nowhere does it mention conversion of probeset IDs to a numeric value. Perhaps what you want to do is convert to Entrez Gene ID?

48khow am i supposed to move ahead i am trying dis from past 10 days but couldnt get the result

20i have generated top 500 genes and saved their rownames in vector rn as

20