String Object Constructors

The String object allows you to manipulate strings of text in a variety of useful ways. You can append characters to Strings, combine Strings through concatenation, get the length of a String, search and replace substrings, and more. This tutorial shows you how to initialize String objects.

String stringOne = "Hello String";                      // using a constant String
String stringOne =  String('a');                        // converting a constant char into a String
String stringTwo =  String("This is a string");         // converting a constant string into a String object
String stringOne =  String(stringTwo + " with more");   // concatenating two strings
String stringOne =  String(13);                         // using a constant integer
String stringOne =  String(analogRead(0), DEC);         // using an int and a base
String stringOne =  String(45, HEX);                    // using an int and a base (hexadecimal)
String stringOne =  String(255, BIN);                   // using an int and a base (binary)
String stringOne =  String(millis(), DEC);              // using a long and a base
String stringOne =  String(5.698, 3);                   // using a float and the decimal places

All of these methods are valid ways to declare a String object. They all result in an object containing a string of characters that can be manipulated using any of the String methods. To see them in action, upload the code below onto an Arduino board and open the Arduino IDE serial monitor. You'll see the results of each declaration. Compare what's printed by each println() to the declaration above it.

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

See Also

• String object - Your Reference for String objects

• CharacterAnalysis - We use the operators that allow us to recognise the type of character we are dealing with.

• StringAdditionOperator - Add strings together in a variety of ways.

• StringAppendOperator - Use the += operator and the concat() method to append things to Strings

• StringCaseChanges - Change the case of a string.

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

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

• StringIndexOf - Look for the first/last instance of a character in a string.

• StringLength - Get the length of a string.

• StringLengthTrim - Get and trim the length of a string.

• StringReplace - Replace individual characters in a string.

• StringStartsWithEndsWith - Check which characters/substrings a given string starts or ends with.

• StringSubstring - Look for "phrases" within a given string.

• StringToInt - Allows you to convert a String to an integer number.

Last revision 2015/08/11 by SM