<commit_before>### String

Strings are an immutable sequence of characters. String literals can be surrounded with double or single quotes.
```swift
	var a = "<NAME>";  // double quotes
	var b = 'Hello World';  // single quotes

	// Strings have also a length property
	var n = b.length;       // n is now 11

	// Strings also have some built in methods
	n = b.index("Wor")      // n is now 6.

	n = b.count("l")        // n is now 3.
	n = b.count("llo")      // n is now 1.

	n = "A".repeat(10)      // n is now "AAAAAAAAAA"

	// upper() and lower() operate on the whole string when 0 arguments are passed
	n = b.upper()           // n is now "HELLO WORLD"
	n = b.lower()           // n is now "hello world"

	// upper() and lower() can both take multiple integer arguments
	n = b.upper(1, -1)     // n is now "HEllo WorlD"<commit_msg>Update string.md<commit_after>### String

Strings are an immutable sequence of characters. String literals can be surrounded with double or single quotes. Gravity supports UTF-8 strings and characters.
```swift
	var a = "Hello World";  // double quotes
	var b = 'Hello World';  // single quotes

	// Strings have also a length property
	var n = b.length;       // n is now 11

	// Strings also have some built in methods
	n = b.index("Wor")      // n is now 6.

	n = b.count("l")        // n is now 3.
	n = b.count("llo")      // n is now 1.

	n = "A".repeat(10)      // n is now "AAAAAAAAAA"

	// upper() and lower() operate on the whole string when 0 arguments are passed
	n = b.upper()           // n is now "HELLO WORLD"
	n = b.lower()           // n is now "hello world"

	// upper() and lower() can both take multiple integer arguments
	n = b.upper(1, -1)     // n is now "HEllo WorlD"
{'fraction_non_alphanumeric': 0.12680949623624782, 'fraction_numerical': 0.012159814707585408, 'mean_word_length': 2.260377358490566, 'pattern_counts': {'":': 0, '<': 4, '<?xml version=': 0, '>': 4, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 2, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
{'dir': 'git-commits-cleaned', 'id': '2431021', 'n_tokens_mistral': 578, 'n_tokens_neox': 540, 'n_words': 245}