Question: This is definitely a rookie question but I'm not finding an answer for this (maybe because of my wording) so here goes:

I'm reading a data frame into R studio (csv file) that has 24 columns with headers. There are only numbers in these columns (they're essentially concentrations of several chemicals). It's called all. I need to use them as numeric vectors. When I read them in and type 

```
is.numeric(all[,1])

```

I get

```
TRUE

```

When I type

```
is.numeric(all[1])

```

I get

```
FALSE

```

I think this is because R interprets the header as a factor. I also tried reading in a table without headers and with `headers=FALSE`, but R renames it to V1, V2 etc so the result ends up being the same.

I need to work with functions where I invoke something like `all[2:24]`. How can I go about to make R either "not see" the header or remove it altogether?

Thanks for the answers!

PS: the dataframe I am using (without headers - if it had headers, it would just have names instead of V1, V2, etc) is something like this:

[![data](https://i.stack.imgur.com/8PbnT.jpg)](https://i.stack.imgur.com/8PbnT.jpg)

Answer: 
As easy as that:

```
var url = document.getElementById("id of element").href;
url = url.substring(0, url.length-1);
url = url + "1";
document.getElementById("id of element").href = url;

```

Probably google first about string functions before asking...
If the pattern of the url stays the same (the parameter `dl=0`) then you can simply use the [`.replace()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace)-function:

```
var url = 'https://www.dropbox.com/sh/wbc1ewhfg1jttpr/AADLfZKlfOBs5e_ueAkzffKRa/SamplePDFDownload.pdf?dl=0';
url = url.replace('dl=0', 'dl=1');

```