String Character Functions

Get/set the value of a specific character in a string.

The String functions

charAt()
and
setCharAt()
are used to get or set the value of a character at a given position in a String.

At their simplest, these functions help you search and replace a given character. For example, the following replaces the colon in a given String with an equals sign:

1String reportString = "SensorReading: 456";
2int colonPosition = reportString.indexOf(':');
3reportString.setCharAt(colonPosition, '=');

Here's an example that checks to see if the first letter of the second word is 'B':

1String reportString = "Franklin, Benjamin";
2int spacePosition = reportString.indexOf(' ');
3if (reportString.charAt(spacePosition + 1) == 'B') {
4Serial.println("You might have found the Benjamins.")
5}

Caution: If you try to get the

charAt
or try to
setCharAt()
a value that's longer than the String's length, you'll get unexpected results. If you're not sure, check to see that the position you want to set or get is less than the string's length using the
length()
function.

Hardware Required

  • Arduino Board

Circuit

There is no circuit for this example, though your board must be connected to your computer via USB and the serial monitor window of the Arduino Software (IDE) should be open.

circuit

Code

Learn more

You can find more basic tutorials in the built-in examples section.

You can also explore the language reference, a detailed collection of the Arduino programming language.

Last revision 2015/08/11 by SM

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