Converting cell contents to a formula

[Neil]

I have a list of quantites in one cell "D4"
"D4" = 6/6 3/2.6 5/1.2.
I need to sum each of these to a total so I use the following formula
=SUBSTITUTE(SUBSTITUTE(TRIM(D4),"/","*")," ","+")
Result: "6*6+3*2.6+5*1.2"
How can I convert the result to a formula that would show the sum 49.8

Thanks for any help.

 

[Biff]

Hi!

You can't "build" a formula like that although it is possible to calculate
the resulting TEXT string but the formula needed to do that would be a mile
long and EXTREMELY difficult to maintain.

So, I have to ask, why are you wanting to do this? Why not put the values in
separate cells?

Biff

 

[Dave Peterson]

You're gonna need some VBA to evaluate the expression.

Option Explicit
Function Eval(myStr As String) As Variant
Eval = Application.Evaluate(myStr)
End Function


Then you'd use:

=eval(SUBSTITUTE(SUBSTITUTE(TRIM(D4),"/","*")," ","+"))
in your cell.

You could do the substitutes in code, too. But then you couldn't use your
=eval() without those substitutions.

Option Explicit
Function Eval(myStr As String) As Variant
With Application
Eval = .Evaluate(.Substitute _
(.Substitute(.Trim(myStr), "/", "*"), " ", "+"))
End With
End Function

Then you'd use:
=eval(d4)

In either case...

If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm

Short course:

Open your workbook.
Hit alt-f11 to get to the VBE (where macros/UDF's live)
hit ctrl-R to view the project explorer
Find your workbook.
should look like: VBAProject (yourfilename.xls)

right click on the project name
Insert, then Module
You should see the code window pop up on the right hand side

Paste the code in there.

Now go back to excel.
Into a test cell and type:
=eval(a1)

 

[Neil]

Thanks for your reply Biff
Dave has given a solution using VBA.
I was thinking along your lines.
The spreadsheet is a copy of how quantity surveyors are used to noting their
material lists
it would be messy if they needed to insert an unknown number of extra rows
as the number of various lengths varies.

 

[Neil]

Thanks Dave
That will work fine.

You're gonna need some VBA to evaluate the expression.

Option Explicit
Function Eval(myStr As String) As Variant
Eval = Application.Evaluate(myStr)
End Function


Then you'd use:

=eval(SUBSTITUTE(SUBSTITUTE(TRIM(D4),"/","*")," ","+"))
in your cell.

You could do the substitutes in code, too. But then you couldn't use your
=eval() without those substitutions.

Option Explicit
Function Eval(myStr As String) As Variant
With Application
Eval = .Evaluate(.Substitute _
(.Substitute(.Trim(myStr), "/", "*"), " ",
"+"))
End With
End Function

Then you'd use:
=eval(d4)

In either case...

If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm

Short course:

Open your workbook.
Hit alt-f11 to get to the VBE (where macros/UDF's live)
hit ctrl-R to view the project explorer
Find your workbook.
should look like: VBAProject (yourfilename.xls)

right click on the project name
Insert, then Module
You should see the code window pop up on the right hand side

Paste the code in there.

Now go back to excel.
Into a test cell and type:
=eval(a1)