Re: string? Or binary garbage?

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Re^2: string? Or binary garbage? by argv (Pilgrim) on Dec 01, 2004 at 01:11 UTC
Given the expense of the application and that it has to ierate over thousands of images at a time, I don't want to look too far into other packages for heavy overhead. Now that I think of it, I just want to see if there are any unprintable control characters... Looking at the perldocs, I should be able to use `$a =~ /\p{IsC}/` [download] ...which says, "crazy control characters and such." However, that seems to be matching legitimate text in some cases. So, I try `$a !~ /\p{IsPrint}/` [download] but that doesn't work either. Then I tried: `$a !~ /\p{IsASCII}/` [download] but that's also not working. I can get into the details on why these things aren't working, but I keep thinking someone's going to pipe in with a statement like, "I ran into this ages ago, and here's a routine that finds all the exceptions..." If not, I suppose I can elaborate on how this isn't working.	[reply] [d/l] [select]
Re^3: string? Or binary garbage? by argv (Pilgrim) on Dec 01, 2004 at 01:57 UTC
Well, I fixed the problem myself. In my previous example, I had: `$a !~ /\p{IsPrint}/` [download] which tests whether $a does NOT match any printing characters. (In other words, the test fails if it DOES match a PRINTABLE character.) So, what I wanted to do is close, but not quite the same thing: `$a =~ /\P{IsPrint}/` [download] which basically tests "does $a match the compliment of a printing character?" In other words, "are there ANY non-printing characters here?" One has to look really closely and speak out the logic into a dark empty room before knowing intuitively which was the right choice ahead of time.	[reply] [d/l] [select]
Re^4: string? Or binary garbage? by hakkr (Chaplain) on Dec 01, 2004 at 15:55 UTC
could you use unpack to do this as well? i.e try and unpack some binary string data and see if it works ..	[reply]