Java - String/Regex matches() for Starts With/Ends With/Contains Check

Parameter:

regex -- the regular expression to which this string is to be matched.

Return Value:

This method returns true if, and only if, this string matches the given regular expression. 

Example:

public class TestRegex {
    public static void main(String args[]){
        String Str = new String("Welcome to pritomkumar.blogspot.com");

        System.out.print("Contains 'pritom': " );
        System.out.println(Str.matches("(.*)pritom(.*)"));

        System.out.print("Starts with 'Welcome': " );
        System.out.println(Str.matches("Welcome(.*)"));

        System.out.print("Ends with '.com': " );
        System.out.println(Str.matches("(.*).com"));

        System.out.print("Starts with small characters: " );
        System.out.println(Str.matches("[a-z](.*)"));

        System.out.print("Starts with cap characters: " );
        System.out.println(Str.matches("[A-Z](.*)"));

        System.out.print("Starts with digits: " );
        System.out.println(Str.matches("[0-9](.*)"));
    }
} 

OUTPUT:

Contains 'pritom': true
Starts with 'Welcome': true
Ends with '.com': true
Starts with small characters: false
Starts with cap characters: true
Starts with digits: false 

 
Table 1.  Common matching symbols

Regular Expression	Description
.	Matches any character
^regex	regex must match at the beginning of the line
regex$	Finds regex must match at the end of the line
[abc]	Set definition, can match the letter a or b or c
[abc][vz]	Set definition, can match a or b or c followed by either v or z
[^abc]	When a "^" appears as the first character inside [] when it negates the pattern. This can match any character except a or b or c
[a-d1-7]	Ranges, letter between a and d and figures from 1 to 7, will not match d1
X|Z	Finds X or Z
XZ	Finds X directly followed by Z
$	Checks if a line end follows

Table 2:  Meta-characters

Regular Expression	Description
\d	Any digit, short for [0-9]
\D	A non-digit, short for [^0-9]
\s	A whitespace character, short for [ \t\n\x0b\r\f]
\S	A non-whitespace character, for short for [^\s]
\w	A word character, short for [a-zA-Z_0-9]
\W	A non-word character [^\w]
\S+	Several non-whitespace characters
\b	Matches a word boundary. A word character is [a-zA-Z0-9_] and \b matches its bounderies.

Table 3: Quantifier

Regular Expression	Description	Examples
*	Occurs zero or more times, is short for {0,}	X* - Finds no or several letter X, .* - any character sequence
+	Occurs one or more times, is short for {1,}	X+ - Finds one or several letter X
?	Occurs no or one times, ? is short for {0,1}	X? -Finds no or exactly one letter X
{X}	Occurs X number of times, {} describes the order of the preceding liberal	\d{3} - Three digits, .{10} - any character sequence of length 10
{X,Y}	Occurs between X and Y times,	\d{1,4}- \d must occur at least once and at a maximum of four
*?	? after a quantifier makes it a reluctant quantifier, it tries to find the smallest match.

jquery find element contains text

eq expects a numerical index to only return a single row. If you want to match a td by its contents, you have to use the :contains selector. Saying "it doesn't work" and throwing it away is not the right approach to the problem, as the selector is (most likely) not at fault (Do note its case sensitive, which might be it...)
Anyhow, if you have a table like this:

<table>
  <tr>
    <td>Hello</td>
    <td>World</td>
  </tr>
  <tr>
    <td>World</td>
    <td>Hello</td>
  </tr>
  <tr>
    <td>Hello</td>
    <td>Hello</td>
  </tr>
</table>

This jQuery code:

$(function() {
    $("td:contains('Hello')").css('color','red');
});

Will turn all cells with "Hello" to red. Demo.
If you need a case insensitive match, you could do this, using the filter function:

$(function() {
    var search = 'HELLO'.toLowerCase();
    $("td").filter(function() {
        return $(this).text().toLowerCase().indexOf(search) != -1;
    }).css('color','red');
});

If you need to match the exact contents of the cell, you could use something similar to the above:

$(function() {
    var search = 'HELLO'.toLowerCase();
    $("td").filter(function() {
        return $(this).text().toLowerCase() == search;
    }).css('color','red');
});

The above is case insensitive (by turning both the search and the contents to lower case when comparing) otherwise you can just remove those if you want case sensitivity. Demo.