kewel
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Checking strings for a only numbers
I need to know if there is a method associated with a class that simply checks wheter a string contains only numbers(these numbers are 0-7). If not, can someone post some code that will tell me how check a string for a value of 0-7? Thanks in advance!
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this will not do it MogalManic because not all numbers are allowed just from 0 to 7, right kewel?
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Regexps are generally very good, I agree.
However, if the task is simply to check for digits 0-7, then using a regexp is an overkill; I have an (untested) suspicion that a regexp is a magnitude more resource intensive than a parseInt().
However, if the task is simply to check for digits 0-7, then using a regexp is an overkill; I have an (untested) suspicion that a regexp is a magnitude more resource intensive than a parseInt().
I have to disagree with gnudiff. I've used regexp quite often and the power they bring is NOT at the expense of overhead (in my opinion admittedly). These pieces of code are optimised so that they take the smartest route to finding the solution and as a rule it's always better to take advantage of the standard api methods rather than role your own. They are also easier to extend and maintain . Imagine if the string gets changed so that it gets pre-fixed with 3 lowercase alphabetic charater, due to expansion requirements, the regexp changes from "([0-7]*)" to "([a-z]{3}[0-7]*)", which is hardly tough.
It is the fact that they are so much more complex to write the first time you use one tends to put people off, but to be honest, go with whatever you feel most comfortable with as it's what you'll use again and again.
It is the fact that they are so much more complex to write the first time you use one tends to put people off, but to be honest, go with whatever you feel most comfortable with as it's what you'll use again and again.
Well, it is the specifics of the case.
Whenever we are talking general string manipulation, there can be tons of ways of using a regexp effectively. And there I would agree with you completely. I like regexps myself, and a regexp is frequently (due to internal optimization) better than lots of String functions.
However, I will have a hard time believing the regexp engine itself could be more efficient than a simple internal
int i=Integer.parseInt(str, 8);
If it is, then I think the Java engine is in serious need of optimization.
Whenever we are talking general string manipulation, there can be tons of ways of using a regexp effectively. And there I would agree with you completely. I like regexps myself, and a regexp is frequently (due to internal optimization) better than lots of String functions.
However, I will have a hard time believing the regexp engine itself could be more efficient than a simple internal
int i=Integer.parseInt(str, 8);
If it is, then I think the Java engine is in serious need of optimization.
public boolean isNumber()
{
try {
Integer.valueOf(str)
return true;
} catch (NumberFormatException x)
return false;
}
}