<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
Write 12 examples of regex strings using proper syntax. Display in table format. In the first column, write the string. In the second column, write what it does. In the third column, write where you would use it, and where it should be included in your file. In the fourth column, break it down and explain each part in detail. 

...//<|im_end|>
<|im_start|>assistant
Here are 12 examples of regex strings:

| Regex String | What it does | Where to use it | Explanation |
| --- | --- | --- | --- |
| `^a` | Matches any string that starts with an "a" character. | Can be used in text validation or search. Include it in the code where you need to validate or search for text. | `^` is an anchor that matches the start of a string. `a` is a character set that matches the "a" character. |
| `\d{3}` | Matches any string that contains exactly 3 digits. | Can be used in text validation or search. Include it in the code where you need to validate or search for text. | `\d` is a shorthand character set that matches any digit (0-9). `{3}` is a quantifier that specifies exactly 3 occurrences of the preceding element (in this case, `\d`). |
| `[A-Z]` | Matches any string that contains an uppercase letter from A to Z. | Can be used in text validation or search. Include it in the code where you need to validate or search for text. | `[A-Z]` is a character set that matches any uppercase letter from A to Z (inclusive). |
| `[aeiou]` | Matches any string that contains a vowel (lowercase). | Can be used in text validation or search. Include it in the code where you need to validate or search for text. | `[aeiou]` is a character set that matches any lowercase vowel (a, e, i, o, u). |
| `[^0-9]` | Matches any string that does not contain digits from 0 to 9.| Can be used in text validation or search. Include it in the code where you need to validate or search for text.| `[^0-9]` is a negated character set which means it will match anything except characters between 0 and 9 inclusive|
|`\w+@\w+\.\w+`|Matches email addresses.|Can be used when validating email addresses.|`\w+` matches one or more word characters before and after '@' sign and before '.' sign; '@' and '.' signs match themselves; `\w+` after '.' sign matches one or more word characters|
|`\bcat\b`|Matches whole word 'cat'.|\b asserts position at word boundary; can be used when searching for whole words only.|`\bcat\b`: '\b' before 'cat' ensures there's no word character before 'c'; 'cat' matches itself; '\b' after 't' ensures there's no word character after 't'.|
|
| `^.{3}$` | Matches any string that is exactly 3 characters long. | Can be used in text validation or search. Include it in the code where you need to validate or search for text. | `^` is an anchor that matches the start of a string. `.` is a character set that matches any character except line breaks. `{3}` is a quantifier that specifies exactly 3 occurrences of the preceding element (in this case, `.`). `$` is an anchor that matches the end of a string. |
| `\b\w{4}\b` | Matches any word that is exactly 4 characters long. | Can be used in text validation or search. Include it in the code where you need to validate or search for text. | `\b` is a word boundary that matches the position between a word character and a non-word character. `\w` is a shorthand character set that matches any word character (alphanumeric and underscore). `{4}` is a quantifier that specifies exactly 4 occurrences of the preceding element (in this case, `\w`). |
| `[a-z]{2,}` | Matches any string that contains at least 2 lowercase letters from a to z.| Can be used in text validation or search. Include it in the code where you need to validate or search for text.| `[a-z]` is a character set which means it will match characters between 'a' and 'z' inclusive; `{2,}` means at least two occurrences|
|`\d{3}-\d{2}-\d{4}`|Matches social security numbers.|Can be used when validating social security numbers.|`\d{3}` matches three digits; '-' sign matches itself; `\d{2}` matches two digits; '-' sign matches itself; `\d{4}` matches four digits|
|`(https?://)?(www\.)?(\w+)(\.\w+)+`|Matches URLs.|Can be used when validating URLs.|`(https?://)?`: 'http' followed by optional 's', followed by '://' - all optional; `(www\.)?`: 'www.' - optional; `(\w+)`: one or more word characters; `(\.\w+)+`: '.' followed by one or more word characters - one or more times|<|im_end|>
<|im_start|>user
Other than the characters you listed, what can \s match?<|im_end|>
<|im_start|>assistant
In addition to matching the whitespace characters like space, tab, and newline, the `\s` character class in regular expressions can also match other Unicode whitespace characters. These may include characters like the non-breaking space, the em space, the en space, and various other space-like characters in different languages and writing systems.<|im_end|>
<|im_start|>user
Reformat your answer, it looks very bad<|im_end|>
<|im_start|>assistant
| Regex String | Description                                          | Use Case                                               | Explanation                                                                 |
|--------------|------------------------------------------------------|--------------------------------------------------------|-----------------------------------------------------------------------------|
| ^abc         | Matches any string that starts with "abc"            | To find lines in a text file that start with "abc"     | ^ asserts the start of a line, and abc is the literal string                |
| abc$         | Matches any string that ends with "abc"              | To find lines in a text file that end with "abc"       | abc is the literal string, and $ asserts the end of a line                  |
| a.b          | Matches any string containing "a", any character, and then "b" | To find occurrences of "a" followed by any character and then "b" | a and b are literal characters, and . matches any character except a newline |
| \d{2,4}      | Matches a sequence of 2 to 4 digits                  | To validate ayear input with 2 to 4 digits                        | \d matches any digit, and {2,4} specifies a range of 2 to 4 occurrences        |
| [A-Za-z]      | Matches any single uppercase or lowercase letter | To find single letters in a text file | [A-Za-z] defines a character class containing all uppercase and lowercase letters |
| [^0-9]       | Matches any character that is not a digit          | To find non-digit characters in a text file | [^0-9] defines a character class with a negation (^) and a range for digits (0-9) |
| (abc\|def)   | Matches either "abc" or "def"                      | To find occurrences of either "abc" or "def" in a text file | (abc\|def) uses the \| symbol to indicate either "abc" or "def"                |
| a{3}         | Matches exactly three consecutive "a" characters   | To find occurrences of "aaa" in a text file | a is the literal character, and {3} specifies exactly 3 occurrences            |
| \bword\b | Matches the word "word" as a whole word | To search for the whole word "word" in a text file | \b asserts a word boundary, and word is the literal string |
| (?i)abc      | Matches "abc" case-insensitively                   | To find occurrences of "abc" regardless of case | (?i) sets the case-insensitive flag, and abc is the literal string |
| (\d+)\s+     | Matches one or more digits followed by one or more whitespace characters | To find and separate numbers followed by spaces in a text file | (\d+) captures one or more digits, and \s+ matches one or more whitespace characters |
| (?<=@)\w+    | Matches a word that follows the "@" symbol         | To extract usernames from email addresses | (?<=@) is a positive lookbehind for the "@" symbol, and \w+ matches one or more word characters |<|im_end|>