Re: Fwd: gawk: numeric comparison on 'sub()' resulted ${n} vars does not work properly

[Stephen Dowdy]

On 2/8/20 11:55 AM, Andrew J. Schorr wrote:

> The problem you're encountering is that the call to sub changes the character
> of $1 from strnum to string. For example:
>
> bash-4.2$ echo 55 | ./gawk '{print typeof($1); sub("5","",$1); print typeof($1); if 
> ($1>40) printf("[%s][%d]\n",$1,$1)}
> '
> strnum
> string
> [5][5]
>
> So you're getting a string comparison. The simple fix is to force a numeric 
> comparision,
> like so:
>
> bash-4.2$ echo 55 | ./gawk '{print typeof($1); sub("5","",$1); print typeof($1); if 
> ($1+0>40) printf("[%s][%d]\n",$1,$1)}
> '
> strnum
> string


Andy, thanks for the pointer to the 'gawk' specific 'typeof()' function (mawk 
doesn't have that).

Here's something from the 'gawk' man page, however:


[ Variable Typing And Conversion ]
...
When a string must be converted to a number, the conversion is accomplished 
using strtod(3)
...
If one value is numeric and the other has a string value that is a
"numeric string," then comparisons are also done numerically.
You say, "i would argue that THIS condition holds true for my comparison."


I would argue that my initial test fits the second part of the quote above.  it may be a 
string type, but it contains a "numeric" value.  So, a numeric test should have 
been performed.  (from my reading)

Am i still missing something?   Does the man page require correction?

thanks,
--stephen