Understanding the JavaScript RegExp Object - In Splits (Page 6 of 11 )
The String object also comes with a split() method, which can be used to decompose a single string into separate units on the basis of a particular separator value; these units are then placed into an array for further processing. Consider the following example, which demonstrates:
<script language="Javascript">
// set string
var friends = "Joey, Rachel, Monica, Chandler, Ross,
Phoebe";
// split into array using commas
var arr = friends.split(", ");
// iterate through array and print each value
for (x=0; x<arr.length;
x++)
{
alert("Hiya, " + arr[x]);
}
</script>
Up until JavaScript 1.1, you could only use string values as separators. JavaScript 1.2 changed all that; now, you can even split a string on the basis of a regular expression.
To understand this better, consider the following string, which illustrates a common problem: unequal whitespace between separated values:
Neo
| Trinity |Morpheus |
Smith| Tank
Here, the | character is used to separate the various names. However, the space between the various | is unequal - which means that before you can use the individual elements of the string, you will need to trim the additional space around them. Splitting by using a regular expression as the separator is an elegant solution to the problem - as you can see from the updated listing below:
<script language="JavaScript">
// define string
var str = "Neo| Trinity
|Morpheus | Smith| Tank";
// define pattern
var pattern = /s*|s*/;
// split the string using the regular expression as the separator
result =
str.split(pattern);
// iterate over result array
for(i = 0; i < result.length; i++)
{
alert("Character #" + (i+1) + ": " + result[i]);
}
</script>
The output of the call to split() above will be an array containing the names, without any leading or trailing spaces.
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