[Bioperl-l] limiting E value - Argument "e-134" isn't numeric?

[Chris Dwan (CCGB)]

> You must be using NCBI-BLAST. NCBI has a problem in that they don't
> include the '1' before E-values less than or equal to 1e-100. So, any
> e-value you get back needs to be checked for '^e' and have a '1' added
> on so it evaluates as a number.

Once upon a time, I dug through the BLAST code to understand exactly this
issue (how e-values are formatted for printing).  This was the code then,
though I make no representations about how it looks now:

if (evalue < 1.0e-180)     { sprintf(eval_buff, "0.0"); }
else if (evalue < 1.0e-99) {
   sprintf(eval_buff, "%2.0Le", evalue);
   eval_buff_ptr++;     /* Knock off digit. */
}
else if (evalue < 0.0009)  { sprintf(eval_buff, "%3.0Le", evalue); }
else if (evalue < 0.1)     { sprintf(eval_buff, "%4.3Lf", evalue); }
else if (evalue < 1.0)     { sprintf(eval_buff, "%3.2Lf", evalue); }
else if (evalue < 10.0)    { sprintf(eval_buff, "%2.1Lf", evalue); }
else                       { sprintf(eval_buff, "%5.0Lf", evalue); }

-Chris Dwan