Strings - Dart - OneCompiler

Strings are one of the most fundamental data types in Dart, used to represent text. Think of strings as a sequence of characters - like words, sentences, or any text you might want to work with in your program.

What is a String?

A string in Dart is a sequence of UTF-16 code units. In simple terms, it's just text! Whether it's a single character, a word, a sentence, or even an entire paragraph - it's all considered a string.

Creating Strings

In Dart, you can create strings using either single quotes (') or double quotes ("). Both work exactly the same way:

String greeting = 'Hello, World!';
String message = "Welcome to Dart programming!";
String singleChar = 'A';
String emptyString = '';

Multi-line Strings

Sometimes you need to work with text that spans multiple lines. Dart provides triple quotes for this:

String multiLine = '''
This is a multi-line string.
It can span across multiple lines
without any special escape characters.
''';

String anotherMultiLine = """
You can also use triple double quotes
for multi-line strings.
Both work the same way!
""";

Raw Strings

Raw strings are useful when you want to include special characters without them being interpreted as escape sequences. Just prefix your string with r:

String rawString = r'This is a raw string with \n and \t';
String filePath = r'C:\Users\Documents\file.txt';

String Properties

Strings come with some handy built-in properties:

String text = 'Hello Dart';

print(text.length);        // Output: 10
print(text.isEmpty);       // Output: false
print(text.isNotEmpty);    // Output: true

String empty = '';
print(empty.isEmpty);      // Output: true

Accessing Characters

You can access individual characters in a string using square brackets with an index (starting from 0):

String word = 'Dart';

print(word[0]);  // Output: D
print(word[1]);  // Output: a
print(word[2]);  // Output: r
print(word[3]);  // Output: t

String Concatenation

You can combine strings using the + operator:

String firstName = 'John';
String lastName = 'Doe';
String fullName = firstName + ' ' + lastName;
print(fullName);  // Output: John Doe

Escape Sequences

Sometimes you need to include special characters in your strings. Use escape sequences with a backslash (\):

Escape Sequence	Description
`\n`	New line
`\t`	Tab
`\'`	Single quote
`\"`	Double quote
`\\`	Backslash

String text = 'She said, "Hello!\nHow are you?"';
String path = 'C:\\Users\\Documents';
String quote = 'It\'s a beautiful day!';

String Comparison

You can compare strings using comparison operators:

String str1 = 'apple';
String str2 = 'banana';
String str3 = 'apple';

print(str1 == str3);  // Output: true
print(str1 == str2);  // Output: false
print(str1.compareTo(str2));  // Output: negative number (str1 < str2)

Strings are case-sensitive, so 'Hello' and 'hello' are considered different strings. Understanding these string basics will give you a solid foundation for working with text in your Dart programs!

String Basics