Can you nest SUBSTITUTE in an IF syntax?

[Nanaia]

Is it possible to nest SUBSTITUTE within an IF formula? I have a column that has a range of numbers in it that I want to combine in a TEXTJOIN string. However IF the number is a decimal, I need to substitute the decimal with an underscore. i.e. instead of 6.875 it needs to be 6_875. I'm not sure how to do it though. Can anyone help?
Thanks.

If you want more details, just let me know.
[TABLE="width: 500"]
<tbody>[TR]
[TD]DRW[/TD]
[TD]FACE[/TD]
[TD]TEXTJOIN[/TD]
[/TR]
[TR]
[TD]25[/TD]
[TD]6.875[/TD]
[TD]25_6_875[/TD]
[/TR]
[TR]
[TD]25[/TD]
[TD]11.375[/TD]
[TD]25_11_375[/TD]
[/TR]
[TR]
[TD]18A[/TD]
[TD]36[/TD]
[TD]18A_36[/TD]
[/TR]
</tbody>[/TABLE]

 

[brharrii]

Would this work:

=Concatenate(DRW, Substitute(FACE, ".", "_"))

 

[AlKey]

Try this

[B]=SUBSTITUTE(A1&"."&B1,".","_")[/B]

 

[Nanaia]

bharrii - this brought me very close to what I wanted, however I needed an underscore between the DRW and the FACE as well as where the decimal is. Thank you for your help though!

 

[Nanaia]

AlKey - you gave me the idea to just plug the substitute into my TEXTJOIN formula again. I tried it without the IF portion and it worked! I must've been over thinking it. (Go figure) Thanks for your help!

 

[brharrii]

bharrii - this brought me very close to what I wanted, however I needed an underscore between the DRW and the FACE as well as where the decimal is. Thank you for your help though!

To add the underscore:

=Concatenate(DRW, "_", Substitute(FACE, ".", "_"))