# Turn code into function
**URL:** https://discourse.julialang.org/t/turn-code-into-function/42147
**Category:** New to Julia
**Created:** [June 27, 2020, 6:55am UTC](https://discourse.julialang.org/t/turn-code-into-function/42147 "2020-06-27T06:55:54Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@colinclout12](https://discourse.julialang.org/u/colinclout12)
#### Post date: [June 27, 2020, 6:55am UTC](https://discourse.julialang.org/t/turn-code-into-function/42147/1 "2020-06-27T06:55:54Z")
(Edited for code legibility.)
I’m having some trouble transitioning from R to Julia. In R, I don’t have to worry if the argument for the function is a scalar or a vector, but in Julia, I get very different results if I try to evaluate a function at stored vector, or at a string of digits. Additionally, in R, I can turn working code into a function, and expect the function to behave exactly like the code does. But, again, in Julia, I can try to turn working code into a function, and get errors when I attempt to call the function. For instance, in R, I can simply define f as:
`f <- function(x){sum(cos(x))}`
(More complicated versions of this sort of function shows up a lot in Benchmark functions.) Once I’ve defined the function, I don’t have to worry if x is a vector or a scalar, and, more importantly, the code in the function will run exactly the same inside the function as outside it.
But in Julia, I cannot get the same sort of function to work, and the code behaves very differently when inside the function than when outside it.
For instance:
```julia
function f(x...)
sum(x)
end
f(2,3)
returns 5, but if I add
q = [2,3]
f(q)
```
I just get [2,3] back.
So sum doesn’t work for vectors, only for a “list” of scalars. Worse, sum(q) returns 5, so the code itself doesn’t work the same in the function as outside it. (And if instead of sum(x), I used cos.(x), f(q) would result in an error, but f(2,3) would work as expected, even though cos.(q) works as expected.)
Perhaps this has something to do with how environments work?? I don’t have to worry about environments in R. But then how do I make my function take vector inputs? And how do I turn working code into a function? Conversely, if my function isn’t behaving like I expect it to, how do I run parts of it outside the function environment (??) to debug it? (Or is there a better way to debug it? Maybe by defining new functions with )
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [June 27, 2020, 7:21am UTC](https://discourse.julialang.org/t/turn-code-into-function/42147/2 "2020-06-27T07:21:37Z")
> [@colinclout12](#):
>
> In R, I don’t have to worry if the argument for the function is a scalar or a vector
Possibly, because R has no scalars, only vectors. 😉
> [@colinclout12](#):
>
> So sum doesn’t work for vectors, only for a “list” of scalars.
In your example, if you call `f` with `[2,3]`, then `x` will be a tuple `([2, 3],)`, so `sum` will sum this tuple.
> [@colinclout12](#):
>
> Perhaps this has something to do with how environments work??
No; also there are no “environments” in the R sense in Julia.
I would recommend that you start from the basics, and work through the Julia manual first. Trying to adapt R concepts to Julia will just be a source of continuous frustration.
Also, please quote your code.
> [@Please read: make it easier to help you](https://discourse.julialang.org/t/psa-make-it-easier-to-help-you/14757/):
>
> Welcome to the Julia Discourse! We are enthusiastic about helping Julia programmers, both beginner and experienced. This public service announcement (PSA) outlines best practices when asking for help. Following these points makes it easier for us to help you and more likely you’ll get a prompt, useful answer. Keywords are highlighted to make it easier to refer to specific points. Choose a descriptive title that captures the key part of your question, eg “plots with multiple axes” instead of …
---
### Author:  [@Skoffer](https://discourse.julialang.org/u/Skoffer)
#### Post date: [June 27, 2020, 8:13am UTC](https://discourse.julialang.org/t/turn-code-into-function/42147/3 "2020-06-27T08:13:09Z")
Also you may find this particular section of the docs interesting [Noteworthy differences from R](https://docs.julialang.org/en/v1/manual/noteworthy-differences/#Noteworthy-differences-from-R-1).
---
### Author:  [@colinclout12](https://discourse.julialang.org/u/colinclout12)
#### Post date: [June 27, 2020, 6:36pm UTC](https://discourse.julialang.org/t/turn-code-into-function/42147/4 "2020-06-27T18:36:18Z")
Thank you!
---
### Author:  [@colinclout12](https://discourse.julialang.org/u/colinclout12)
#### Post date: [June 27, 2020, 6:37pm UTC](https://discourse.julialang.org/t/turn-code-into-function/42147/5 "2020-06-27T18:37:59Z")
Thank you! I think I was struggling because it was late at night and nothing made sense. I think I misunderstood an earlier error, tried to fix it, and introduced a new one without realizing it. But thank you for your help!
Also, sorry for the lack of indents and back-ticks. I’m not used to formatting comboxes for code, and tried to use spaces for indents, and didn’t know how to make it look like code (with back-ticks). The best practice recommendations are much appreciated.