Select Code to Download

$val=$val+0;            # Sum
$val=eval "$val";        # Eval
$val=sprintf("%f", $val);    # Sprintf
    # Call your original technique "Regex"

Sum("1.25e-5")           gives  '1.25e-05'
Regex("1.25e-5")                '1.25e-05'
...
Sum("1.25e-3")                  0.00125
Regex("1.25e-3")                0.00125
Eval("1.25e-3")                 0.00125

Sprintf("1.25e-5")              0.000013
Sprintf("1.25e-3")              0.001250
Sprintf("1.25e-7")              0.000000

sprintf("%.10f", $val)          0.0012500000

Benchmark: timing 100000 iterations of Eval, Regex, Sprintf, SprintfSu
+bst, Sum...
      Eval: 20 wallclock secs (19.58 usr +  0.00 sys = 19.58 CPU)
...
   Sprintf:  7 wallclock secs ( 6.22 usr +  0.00 sys =  6.22 CPU)
SprintfSubst:  8 wallclock secs ( 8.74 usr +  0.00 sys =  8.74 CPU)
       Sum:  4 wallclock secs ( 3.52 usr +  0.00 sys =  3.52 CPU)

#!/usr/bin/perl

...
                   Sprintf => sub { Sprintf("1.25e-3") },
                   SprintfSubst => sub { SprintfSubst("1.25e-3") },
                  });