Energia

Examples > Strings

### String Replace Function

The String replace() function allows you to replace all instances of a given character with another character. You can also use replace to replace substrings of a string with a different substring.

### Relevant Groundwork

None

### Hardware Required

- MSP-EXP430G2 LaunchPad

### Circuit

Only LaunchPad is required for this example.

image developed using Fritzing. For more circuit examples, see the Fritzing project page.

### Schematic

### Code Explanation

Caution: If you try to replace a substring that's more than the whole string itself, nothing will be replaced. For example:.

      String stringOne = "dog";
      String stringTwo = stringOne.replace("twodogs", "Blah");

In this case, the code will compile, but stringOne will remain unchanged, since the replacement substring is more than the String itself.

### Code

    /*
      String replace()

     Examples of how to replace characters or substrings of a string

     created 27 July 2010
     modified 2 Apr 2012
     by Tom Igoe

     This example code is in the public domain.
     */

    void setup() {
      // Open serial communications and wait for port to open:
      Serial.begin(9600);

      // send an intro:
      Serial.println("\n\nString  replace:\n");
      Serial.println();
    }

    void loop() {
      String stringOne = "<HTML><HEAD><BODY>"";
      Serial.println(stringOne);
      // replace() changes all instances of one substring with another:
      // first, make a copy of th original string:
      String stringTwo = stringOne;
      // then perform the replacements:
      stringTwo.replace("<", "</");
      // print the original:
      Serial.println("Original string: " + stringOne);
      // and print the modified string:
      Serial.println("Modified string: " + stringTwo);

      // you can also use replace() on single characters:
      String normalString = "bookkeeper";
      Serial.println("normal: " + normalString);
      String leetString = normalString;
      leetString.replace('o', '0');
      leetString.replace('e', '3');
      Serial.println("l33tspeak: " + leetString);

      // do nothing while true:
      while(true);
    }

### Working Video

(Insert Video Here)

### Try it out:

- Replace all the nouns in a string with funny names

See Also

- setup()
- loop()
- println()

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The text of the Energia reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Energia reference is based on the Arduino reference. Code samples in the reference are released into the public domain.

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