Arduino-Development / examples /08.Strings /StringComparisonOperators /StringComparisonOperators.ino
| /* | |
| Comparing Strings | |
| Examples of how to compare Strings using the comparison operators | |
| created 27 Jul 2010 | |
| modified 2 Apr 2012 | |
| by Tom Igoe | |
| This example code is in the public domain. | |
| https://www.arduino.cc/en/Tutorial/BuiltInExamples/StringComparisonOperators | |
| */ | |
| String stringOne, stringTwo; | |
| void setup() { | |
| // Open serial communications and wait for port to open: | |
| Serial.begin(9600); | |
| while (!Serial) { | |
| ; // wait for serial port to connect. Needed for native USB port only | |
| } | |
| stringOne = String("this"); | |
| stringTwo = String("that"); | |
| // send an intro: | |
| Serial.println("\n\nComparing Strings:"); | |
| Serial.println(); | |
| } | |
| void loop() { | |
| // two Strings equal: | |
| if (stringOne == "this") { | |
| Serial.println("StringOne == \"this\""); | |
| } | |
| // two Strings not equal: | |
| if (stringOne != stringTwo) { | |
| Serial.println(stringOne + " =! " + stringTwo); | |
| } | |
| // two Strings not equal (case sensitivity matters): | |
| stringOne = "This"; | |
| stringTwo = "this"; | |
| if (stringOne != stringTwo) { | |
| Serial.println(stringOne + " =! " + stringTwo); | |
| } | |
| // you can also use equals() to see if two Strings are the same: | |
| if (stringOne.equals(stringTwo)) { | |
| Serial.println(stringOne + " equals " + stringTwo); | |
| } else { | |
| Serial.println(stringOne + " does not equal " + stringTwo); | |
| } | |
| // or perhaps you want to ignore case: | |
| if (stringOne.equalsIgnoreCase(stringTwo)) { | |
| Serial.println(stringOne + " equals (ignoring case) " + stringTwo); | |
| } else { | |
| Serial.println(stringOne + " does not equal (ignoring case) " + stringTwo); | |
| } | |
| // a numeric String compared to the number it represents: | |
| stringOne = "1"; | |
| int numberOne = 1; | |
| if (stringOne.toInt() == numberOne) { | |
| Serial.println(stringOne + " = " + numberOne); | |
| } | |
| // two numeric Strings compared: | |
| stringOne = "2"; | |
| stringTwo = "1"; | |
| if (stringOne >= stringTwo) { | |
| Serial.println(stringOne + " >= " + stringTwo); | |
| } | |
| // comparison operators can be used to compare Strings for alphabetic sorting too: | |
| stringOne = String("Brown"); | |
| if (stringOne < "Charles") { | |
| Serial.println(stringOne + " < Charles"); | |
| } | |
| if (stringOne > "Adams") { | |
| Serial.println(stringOne + " > Adams"); | |
| } | |
| if (stringOne <= "Browne") { | |
| Serial.println(stringOne + " <= Browne"); | |
| } | |
| if (stringOne >= "Brow") { | |
| Serial.println(stringOne + " >= Brow"); | |
| } | |
| // the compareTo() operator also allows you to compare Strings | |
| // it evaluates on the first character that's different. | |
| // if the first character of the String you're comparing to comes first in | |
| // alphanumeric order, then compareTo() is greater than 0: | |
| stringOne = "Cucumber"; | |
| stringTwo = "Cucuracha"; | |
| if (stringOne.compareTo(stringTwo) < 0) { | |
| Serial.println(stringOne + " comes before " + stringTwo); | |
| } else { | |
| Serial.println(stringOne + " comes after " + stringTwo); | |
| } | |
| delay(10000); // because the next part is a loop: | |
| // compareTo() is handy when you've got Strings with numbers in them too: | |
| while (true) { | |
| stringOne = "Sensor: "; | |
| stringTwo = "Sensor: "; | |
| stringOne += analogRead(A0); | |
| stringTwo += analogRead(A5); | |
| if (stringOne.compareTo(stringTwo) < 0) { | |
| Serial.println(stringOne + " comes before " + stringTwo); | |
| } else { | |
| Serial.println(stringOne + " comes after " + stringTwo); | |
| } | |
| } | |
| } | |