[string].indexOf(searchValue)
Category:Variables
In apps you sometimes need to check if one string is contained in another string, and if so, where. For example, to split comma delimted data into individual data fields. indexOf() returns a the numeric position where the searchString was first found in the string, else it returns -1 if =not found. To call the indexOf function you need use a variable containing a string, followed by a dot ("."), followed by the function name "indexof()" with a string argument or variable of what to search for.
Examples
Example: Question Check
// See if a sentence is a question or not.
var sentence="How old are you?";
console.log(sentence.indexOf("?") == (sentence.length-1));
Example: Original Gettysburg Address
Demonstrate that indexOf() is case sensitive.
// Demonstrate that indexOf is case sensitive.
var gettysburgAddress="Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.";
console.log(gettysburgAddress.indexOf("Four"));
console.log(gettysburgAddress.indexOf("four"));
Example: Parse Comma-Delimited Data
Parse a comma-delimted string into fields.
// Parse a comma-delimted string into fields.
var data="Titantic,1997,James Cameron,PG-13";
var commaPosition=data.indexOf(",");
while (commaPosition!=-1) {
console.log(data.substring(0,commaPosition));
data=data.substring(commaPosition+1,data.length);
commaPosition=data.indexOf(",");
}
console.log(data);
Syntax
[string].indexOf(searchValue)
Parameters
| Name | Type | Required? | Description |
|---|---|---|---|
| string | string | The string to search. | |
| searchValue | string | The string to search for. |
Returns
Returns the position of the first occurrence of *searchValue* within the string, else returns -1 if not found.
Tips
- The search is a case-sensitive search.
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