first touch to Regex

heavenflying

Oh, I haven’t come here for two weeks. What I am busy with is coding. I should complete all the coding tasks. Bad luck! I must code day after day until the code is over. I’ll recall the problems I encountered those days, and record here to share with all of you. Ok, let’s discuss the problems start with Regex (Regular Expression).

The following explanation to define the regular expression is cited from the java tutorials of Sun Microsystems Corporation. Regular expressions are a way to describe a set of strings based on common characteristics shared by each string in the set. They can be used to search, edit, or manipulate text and data. You must learn a specific syntax to create regular expressions — one that goes beyond the normal syntax of the Java programming language. Regular expressions vary in complexity, but once you understand the basics of how they're constructed, you'll be able to decipher (or create) any regular expression.

I haven’t used the regular expressions before I have to solve how to check whether the IP address format is right or wrong. I haven’t dealt with the similar problem since I entered the college. Now, I’m in the corporation, not in the college. I opened the browser and search how to check IP address. Of course, I found abundant information about it. I think it’s the best way to check IP address with regular expression. The following JavaScript codes show the power of the regular expression.
function checkIp(ipAddress){ var exp=/^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$/;
var reg=ipAddress.match(exp);
if(reg==null)  {
       return false;
}else{
       return true;
}
}
You can judge some string is blank or not with the following javascript function.
function checkBlank(input){
    return Boolean( /^\s*$/.test( input ) );
}
Of course, you can do many things with regular expressions. You can search, edit, or manipulate text and data with abbreviated regular expressions. I’m a novice to it. I decide to learn it earnestly and master it!




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