I would like to know if Regular Expressions are Universal for all languages like PHP, Javascript, etc.?
Source: Tips4all, CCNA FINAL EXAM
Source: Tips4all, CCNA FINAL EXAM
I have a 2.67 GHz Celeron processor, 1.21 GB of RAM on a x86 Windows XP Professional machine. My understanding is that the Android emulator should start fairly quickly on such a machine, but for me it does not. I have followed all instructions in setting up the IDE, SDKs, JDKs and such and have had some success in staring the emulator quickly but is very particulary. How can I, if possible, fix this problem?
Your question is kind of ambiguous to me: You must define what you mean with Universal, but here's my answer:
ReplyDeleteRegular Expressions are used in almost every programming language like PHP, JavaScript, Perl, Awk, Java, C#, etc...
The thing is that the syntax may vary a little bit from one language to another, and each language may implement them in a different way, and include or not some particular features (usually features that allow regex to recognize not only regular languages, but also others like Context-Free ones)
If you create a new programming language, you can add them regexes feature, but that doesn't mean the syntax will be exactly the same as regexes syntax in .NET, for example. And not only that: The implementation of the engine will surely be different (more/less efficient) than others...
They're not all exactly the same
ReplyDeleteTake a look at this list for some of the differences
No. There are many dialects of regular expressions, though the basic expressions tend to be quite similar. Also, a useful feature introduced in one dialect is often copied by other dialects.
ReplyDeleteRegular expressions in themselves are a programming construct. So you'll find that the core concepts regarding expressions for pattern matching are basically universal, however each implementation will provide their specific spin on the syntax to go about accomplishing that.
ReplyDeleteNo. But anything you are likely to use will support them in some shape or form.
ReplyDeleteThe bad news is no!
ReplyDeleteThere are many implementations and variations of regexes.
In a standard unix implementation ksh, bash, grep and awk all use slightly different rules. lua has a very limited regex library and Java has a fully functioning lib but with its own quirks.
The good news is that most of the popular scripting (php, python etc.) languages use "pcre" library and as "pcre" stands for "Perl Compatable Regular Expresions" by definition it works the same as perl regular expressions as far as possible. And the pcre library is linkable from to compiled languages (C,C++ etc).