String substring Function

The String function

substring()

charAt()

startsWith()

endsWith()

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.

Code

substring()

Copy
1String stringOne = "Content-Type: text/html";
2// substring(index) looks for the substring from the index position to the end:
3if (stringOne.substring(19) == "html") {
4}

is true, while

Copy
1String stringOne = "Content-Type: text/html";
2// substring(index) looks for the substring from the index position to the end:
3if (stringOne.substring(19) == "htm") {
4}

is not true, because there's an

l

htm

substring()

Copy
1String stringOne = "Content-Type: text/html";
2// you can also look for a substring in the middle of a string:
3if (stringOne.substring(14,18) == "text") {
4}

This looks for the word

text

Caution: make sure your index values are within the String's length or you'll get unpredictable results. This kind of error can be particularly hard to find with the second instance of

substring()

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