title: "String()" categories: [ "Data Types" ] subCategories: [ "StringObject Function" ] ---
Constructs an instance of the String class. There are multiple versions that construct Strings from different data types (i.e. format them as sequences of characters), including:
-
a constant string of characters, in double quotes (i.e. a char array)
-
a single constant character, in single quotes
-
another instance of the String object
-
a constant integer or long integer
-
a constant integer or long integer, using a specified base
-
an integer or long integer variable
-
an integer or long integer variable, using a specified base
-
a float or double, using a specified decimal palces
Constructing a String from a number results in a string that contains the ASCII representation of that number. The default is base ten, so
String thisString = String(13);
gives you the String "13". You can use other bases, however. For example,
String thisString = String(13, HEX);
gives you the String "D", which is the hexadecimal representation of the decimal value 13. Or if you prefer binary,
String thisString = String(13, BIN);
gives you the String "1101", which is the binary representation of 13.
String(val)
String(val, base)
String(val, decimalPlaces)
val
: a variable to format as a String - Allowed data types: string, char, byte, int, long, unsigned int, unsigned long, float, double
an instance of the String class.
All of the following are valid declarations for Strings.
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
-
LANGUAGE charAt()
-
LANGUAGE compareTo()
-
LANGUAGE concat()
-
LANGUAGE c_str()
-
LANGUAGE endsWith()
-
LANGUAGE equals()
-
LANGUAGE equalsIgnoreCase()
-
LANGUAGE getBytes()
-
LANGUAGE indexOf()
-
LANGUAGE lastIndexOf()
-
LANGUAGE length()
-
LANGUAGE remove()
-
LANGUAGE replace()
-
LANGUAGE reserve()
-
LANGUAGE setCharAt()
-
LANGUAGE StartsWith()
-
LANGUAGE substring()
-
LANGUAGE toCharArray()
-
LANGUAGE toInt()
-
LANGUAGE toFloat()
-
LANGUAGE toLowerCase()
-
LANGUAGE toUpperCase()
-
LANGUAGE trim()
-
LANGUAGE [] (element access)
-
LANGUAGE + (concatenation)
-
LANGUAGE += (append)
-
LANGUAGE == (comparison)
-
LANGUAGE > (greater than)
-
LANGUAGE >= (greater than or equal to)
-
LANGUAGE < (less than)
-
LANGUAGE <= (less than or equal to)
-
LANGUAGE != (different from)
-
EXAMPLE link: Built-in String Tutorials