Reference for Wiring version 0027+. If you have a previous version, use the reference included with your software. If you see any errors or have any comments, let us know.
Name |
String |
Examples |
// declares s1 with an initial string
String s1 = String("string number one");
byte bytes[20]; // array of bytes
char array[20]; // array of chars
void setup() {
Serial.begin(9600);
// turn ON wiring hardware LED
pinMode(48, OUTPUT);
digitalWrite(48, HIGH);
// s2 holds "10000"
String s2 = String(10000);
Serial.println("s2 holds: " + s2);
// s3 holds "567000"
String s3 = String(567000, DEC);
Serial.println("s3 holds: " + s3);
// s4 holds "string number four"
String s4 = "string number four";
Serial.println("s4 holds: " + s4);
// use + operator to add a string
s4 += " plus another part";
// user + operator when printing to serial
Serial.println("now s4 holds: " + s4);
// get character at position 5
char c = s4.charAt(5);
Serial.print("c holds: ");
Serial.println(c); // prints 'g'
// s5 holds "string number one"
String s5 = String("string number one");
int cmp = s1.compareTo(s5); // compare s1 to s5
if(cmp == 0) {
Serial.println("s1 and s5 are equal"); // prints equal
} else {
Serial.println("s1 and s5 are different");
}
// check if s5 ends with "one"
if(s5.endsWith("one"))
// prints "s5 ends with "one""
Serial.println("s5 ends with "one"");
if(s1.equals(s5)) // check if s1 equal to s5
Serial.println("s1 and s5 are equal"); // prints equal
// s6 holds "string NUMBER one"
String s6 = String("string NUMBER one");
// check if s5 and s6 are equal ignoring case differences
if(s5.equalsIgnoreCase(s6))
// prints equal
Serial.println("s6 and s5 are equal ignoring the case");
Serial.print("index of char R pn s6 is: ");
Serial.println(s6.indexOf('R'), DEC); // prints 12
Serial.print("index of char R on s6 from index 13 is: ");
// prints -1, not found
Serial.println(s6.indexOf('R', 13), DEC);
String s7 = s6.substring(7, 13);
Serial.println("s7 is: "+s7); // prints "NUMBER"
Serial.print("index of string "NUMBER" on s6 is: ");
Serial.println(s6.indexOf(s7), DEC); // prints 7
Serial.print("last index of char 'n' on s6 is: ");
Serial.println(s6.lastIndexOf('n'), DEC); // prints 15
Serial.print("length of s6 is: ");
Serial.println(s6.length(), DEC); // prints 15
// set character at index 15 to 'N'
s6.setCharAt(15, 'N');
// prints "string NUMBER oNe"
Serial.println("s6 is: "+s6);
// check if s6 starts with "string"
if(s6.startsWith("string"))
// s6 starts with "string" string
Serial.println("s6 starts with "string"");
// prints "string number one"
Serial.println("s6 to lower case is: "+s6.toLowerCase());
// prints "STRING NUMBER ONE"
Serial.println("s6 to upper case is: "+s6.toUpperCase());
s6.concat(" plus spaces at the end "); // concat a string
// prints "string NUMBER oNe plus spaces at the end "
Serial.println("s6 is: "+s6);
// prints "string NUMBER oNe plus spaces at the end"
Serial.println("trim of s6 is: "+s6.trim());
// prints "string NUMBER oN5 plus spac5s at th5 5nd"
Serial.println("s6 is: "+s6.replace('e', '5'));
// get the byte array in the array bytes
s6.getBytes(bytes, 20);
Serial.print("array bytes is: ");
for(int i=0; i<20; i++) {
// prints "s t r i n g N U M B E R o N e p"
Serial.print(bytes[i]);
Serial.print(" ");
}
Serial.println();
Serial.print("array array is: ");
s6.toCharArray(array, 20);
Serial.println(array); // Prints "string NUMBER oNe p"
}
void loop() {
}
|
Description |
A string is a sequence of characters. The class String includes methods for examining individual characters, comparing strings, searching strings, extracting parts of strings, and for converting an entire string uppercase and lowercase. Strings are always defined inside double quotes ("Abc") and characters are always defined inside single quotes('A').
Note that the Wiring String class has differences with the processing or Java String class. The main difference is that some methods modify the actual string instead of returning a modified copy of it. |
Methods |
charAt() |
Returns the character at the specified index |
compareTo() |
Compares two strings lexicographically |
concat() |
Concatenates the String argument specified |
endsWith() |
Returns true if the current string ends with the input string |
equals() |
Compares a string to a specified string |
equalsIgnoreCase() |
Compares a string to a specified string, ignoring case considerations |
indexOf() |
Returns the index value of the first occurrence of a character or string within the input string |
lastIndexOf() |
Returns the index value of the last occurrence of a character or string within the input string |
length() |
Returns the number of characters in the string |
setCharAt() |
Changes the character specified at the specified index |
startsWith() |
Returns true if the current string starts with the input string |
substring() |
Returns a new string that is part of the input string |
toLowerCase() |
Converts all the characters to lower case |
toUpperCase() |
Converts all the characters to upper case |
trim() |
Returns a copy of the string, with leading and trailing whitespace omitted |
getBytes() |
Returns an array of bytes containing the characters of the String as bytes |
toCharArray() |
Returns the content of the specified String as an array of chars |
replace() |
Replaces all the occurrences of a character in a string with the specified character |
|
Constructor |
String(data)
String(data, base) |
Parameters |
data |
byte[], char[]: array of bytes to be decoded into characters or array of characters to be combined into a string, int, long: string conversion of the specified value, String: string to be copied into the created string |
base |
DEC, HEX, OCT or BIN (exclusive for int or long data) |
|
Usage |
Application |
Related |
char
|
Updated on September 16, 2010 11:34:09pm PDT