P for Positive » Programming

Trim Last Character(s) from a String in Javascript

admin — Sat, 26 Apr 2008 03:47:00 +0000

Today, I had a need to join comma separated strings in Javascript which turned out to be very easy. I wrote something similar to this

for(var i=0; i < length; i++){
string=string+labels[i]+”,”
}

where string was defined as a var and labels as array.

The difficult part was to remove the last comma. After googling for fifteen minuted, I decided to read the documentation on Strings and found the substring function which turned out to be perfect solution.

string = string.substring(0, string.length-1)

Create .htaccess file in Vista

admin — Wed, 23 Apr 2008 03:31:00 +0000

I enjoy using command line, especially for things that I cannot do using GUI. Today, I spent good 15 minutes trying to create .htaccess file in c:\xampp\htdocs directory on my Vista machine. I guess Vista expects a file name before the period and therefore kept saying ‘You must type a file name’. This DOS command did the trick:

C:\xampp\htdocs> type nul > .htaccess

Once the file was created, I was able to edit it in notepad

Check if Password is Alphanumeric – PHP

admin — Sat, 19 Apr 2008 02:39:00 +0000

A couple of weeks ago, I spent several hours trying to figure out how to check if a password is alphanumeric or not. Following is a function that worked along with explanation.

1 function checkPasswordIsAlphaNumeric($password1){
2 $pattern1 = “/[a-zA-Z]+/”;
3 $pattern2 = “/[0-9]+/”;
4 return ((preg_match($pattern1, $password1)) && (preg_match($pattern2, $password1)));
5 }

Line 1 is simple. We declare a function ‘checkPasswordIsAlphaNumeric’ which takes one argument, password1.

Let’s tease apart the pattern defined in line 2:

- the expression should be enclosed in the delimiters. A common delimiter is forward slash.

- square brackets are used to match a set of characters, also called character class. Any one of the characters inside the square brackets is matched.

- a-zA-Z matches a through z (lower case) or A through Z (upper case)

- + matches one or more of the preceeding pattern

Putting it all together, /[a-zA-Z]+/ matches one or more characters from a through z OR A through Z.

Line 3 is similar to line 2. It matches one or more characters in the range 0 to 9.

Line 4 checks for the presence of an alphabet in the ‘$password1′ string AND also checks for the presence of a digit in ‘$password1′ string. If it finds at least one alphabet and at least one digit, it returns true. Otherwise, it returns false.

Following are some references that helped me decode regular expressions:

http://java.sun.com/docs/books/tutorial/essential/regex/char_classes.html
http://www.webcheatsheet.com/php/regular_expressions.php
http://www.phphacks.com/content/view/31/33/