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String()

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 places
 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. base: (optional) the base in which to format an integral value. decimalPlaces: only if val is float or double. The desired decimal places. An instance of the String class. Данный класс активно выделяет RAM так что обратите внимание, на то что бы ее было достаточно для коректной работы. Более подробней про память: malloc() All String have the following functions supported:
  • charAt()
  • compareTo()
  • c_str()
  • endsWith()
  • equals()
  • equalsIgnoreCase()
  • getBytes()
  • indexOf()
  • lastIndexOf()
  • length()
  • remove()
  • replace()
  • reserve()
  • setCharAt()
  • startsWith()
  • substring()
  • toCharArray()
  • toDouble()
  • toInt()
  • toFloat()
  • toLowerCase()
  • toUpperCase()
  • trim()
 All String have the following operators supported:
  • []
  • +
  • +=
  • ==
  • >
  • >=
  • <
  • <=
  • !=
 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