# Find if a string begins with a specific set of characters in Arduino

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The startsWith() function in Arduino helps you determine if a string starts with a specific set of characters. It returns true if the string starts with the substring you specified, else it returns false. An example implementation is given below −

## Example

void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
String String1 = "AB_Test";
String String2 = "CD_Test";
String substr1 = "AB";
String substr2 = "AB*";
if(String1.startsWith(substr1)){
Serial.print("String1 starts with substr1");
}
if(String2.startsWith(substr1)){
Serial.print("String2 starts with substr1");
}
if(String1.startsWith(substr2)){
Serial.print("String1 starts with substr2");
}
if(String2.startsWith(substr2)){
Serial.print("String2 starts with substr2");
}
}
void loop() {
// put your main code here, to run repeatedly
}

As you can expect, this program will print "String1 starts with substr1" only. The corresponding Serial Monitor output is shown below (the garbage characters in the beginning are programming/ start-up noise) −

## Output

Published on 24-Mar-2021 05:14:01