Get Programming with JavaScript - Listing 7.08
Listing 7.08 - Finding substrings
var message = "We choose to go to the Moon!";
console.log(message.substr(3, 12));
Further Adventures
Listing 7.08 - Finding substrings - Task 2
- Investigate what happens if you omit the second argument when calling substr.
var message = "We choose to go to the Moon!";
console.log(message.substr(3)); // choose to go to the Moon!
console.log(message.substr(10)); // to go to the Moon!
console.log(message.substr(13)); // go to the Moon!
Omitting the second argument returns the rest of the string from the index specified by the first argument.
Listing 7.08 - Finding substrings - Task 3
- What happens if you use negative numbers as arguments?
var message = "We choose to go to the Moon!";
console.log(message.substr(-3)); // on!
console.log(message.substr(-10)); // the Moon!
If the first argument is negative, substr finds its starting index by counting back from the end of the string.
var message = "We choose to go to the Moon!";
console.log(message.substr(3, -3)); //
console.log(message.substr(3, -10)); //
If the second argument is negative, substr returns an empty string.