I have a data set with multiple columns. A sample of the first three columns are as follows:

```
df$a1 <- c("00845", "486", "49392", "04186", "5990")

df$a2 <- c("34580", "**2761**", "27800", "4439", "5849")

df$a3 <- c("0340", "49392", "78831", "70714", "486")

```

I want to create a column df$b which gives me a "1" if any of the columns a1-a15 contain the string "2761".

| a1 | a2 | a3 | ... | a15 | b |
| --- | --- | --- | --- | --- | --- |
| 00845 | 34580 | 0340 | ... | 4280 | 0 |
| 486 | **2761** | 49392 | ... | 25000 | 1 |
| 49392 | 27800 | 78831 | ... | 7955 | 0 |
| 04186 | 4439 | 70714 | ... | 27800 | 0 |
| 5990 | 5849 | 486 | ... | 4400 | 0 |

So far, I've developed the following code:

```
df %>%

  mutate(d = c(0, 1)[(a1:a15 %in% c("2761")) + 1])

```

but it doesn't work. Any help would be greatly appreciated!