I would like to use gsub in R to match all items which are not alphanumeric

Question

I am searching raw twitter snippets using R but keep getting issues where there are non standard Alphanumeric chars such as the following `"Ì†ºÌøÑ"`. I would like to take out all non `[abcdefghijklmnopqrstuvwxyz0123456789]` characters using `gsub`. Can you use `gsub` to specify a replace for those items NOT in `[abcdefghijklmnopqrstuvwxyz0123456789]`?

Accepted Answer

You could simply negate you pattern with `[^ ...]`:

```
x <- "abcdeÌ†ºÌøÑfgh"
gsub("[^A-Za-z0-9]", "", x)
# [1] "abcdefgh"
```

Please note that the class `[:alnum:]` matches all your given special characters. That's why `gsub("[^[:alnum:]]", "", x)` doesn't work.

I would like to use gsub in R to match all items which are not alphanumeric

Solution

Problem