calculate % between two rows

[heman]

I have to colums: "nm" and "update"

To count the inputs i use the folowing codes:

Code: Select all

set cnt [mysqlsel $db "select count(*) from $table WHERE nm = '$text';" -list]
set cnupdt [mysqlsel $db "select count(*) from $table WHERE update = '$text';" -list]

This gives announcemnet liek this:

<botname> 100 releases in db, 50 are updated

Now I want to make a variable that will tell the percentage updates are made from nm

Someting like:

<botname> 100 releases in db, 50 are updated (50%)

Thanks

[nml375]

You probably would like to investigate the expr command.

[heman]

I tried

Code: Select all

set perc [expr { $cnupdt / $cnt * 100 }]

but results is : 0

Am I missing something?

[nml375]

Yup, type conversion and order of operations.
With tcl, if you divide two integers, the result will also be an integer (using truncation). And since percent is less than 1, you'll always get 0.

You'll either have to do the multiplication first, or convert the numbers to floats (I'd say the first is easier)

Try this:

Code: Select all

set perc [expr {($cnupdt*100)/$cnt}]

[heman]

ok that works, sort of.

cnupdt = 7
cnt =175

7 x 100 / 175 = 4 so it announces -> 4


cnupdt = 5
cnt =175

5 x 100 / 175 = 2,86 but it announces -> 2

Is there a way it announce -> 2,86 ?


http://www.tcl.tk/man/tcl8.4/TclCmd/expr.htm

expr 5 / 4

returns 1, while

expr 5 / 4.0

return 1.25

I tried

Code: Select all

set perc [expr {($cnupdt.0*100)/$cnt}]

instead of

set perc [expr {($cnupdt*100)/$cnt}]

But that didnt worked.

[user]

add the ".0" to your static value (100) or remove the braces...

Code: Select all

% set a 3; set b 7
% format %.2f [expr {($a*100.0)/$b}]
42.86
% format %.2f [expr ($a.0*100)/$b]
42.86

[heman]

ok that works, thanks.

Final question

the output now looks like for example:

2.85714285714 %

Is it possible it wil only announce the first one or two after the "." ?

So someting like:

2.85 %

And thanks for all the help

[Sir_Fz]

% format %.2f 2.85714285714
2.86

Edit: user did include that in his code

[metroid]

Using braces in expr is faster so I'd recommend using the first option.