Explore the power of regular expressions
| Name | Preview | Code | Difficulty |
|---|---|---|---|
| Matching Specific String | Match a specific string using regex. | Python | Easy |
| Matching Anything But a Newline | Use [.] in the regex expression to match anything but a newline character. | Python | Easy |
| Matching Digits & Non-Digit Characters | Use the expression \d to match digits and \D to match non-digit characters. | Python | Easy |
| Matching Whitespace & Non-Whitespace Character | Use \s to match whitespace and \S to match non whitespace characters in this challenge. | Python | Easy |
| Matching Word & Non-Word Character | Use \w to match any word and \W to match any non-word character. | Python | Easy |
| Matching Start & End | Use the ^ symbol to match the start of a string, and the $ symbol to match the end characters. | Python | Easy |
| Name | Preview | Code | Difficulty |
|---|---|---|---|
| Matching Specific Characters | Use the [ ] expression to match specific characters. | Python | Easy |
| Excluding Specific Characters | Use the [^] character class to exclude specific characters. | Python | Easy |
| Matching Character Ranges | Write a RegEx matching a range of characters. | Python | Easy |
| Name | Preview | Code | Difficulty |
|---|---|---|---|
| Matching {x} Repetitions | Match exactly x repetitions using the tool {x}. | Python | Easy |
| Matching {x, y} Repetitions | Match between a range of x and y repetitions using the {x,y} tool. | Python | Easy |
| Matching Zero Or More Repetitions | Match zero or more repetitions of character/character class/group using the * symbol in regex. | Python | Easy |
| Matching One Or More Repetitions | Match zero or more repetitions of character/character class/group with the + symbol. | Python | Easy |
| Matching Ending Items | Match the end of the string using the $ boundary matcher. | Python | Easy |
| Name | Preview | Code | Difficulty |
|---|---|---|---|
| Matching Word Boundaries | Using \b to match word boundaries. | Python | Easy |
| Capturing & Non-Capturing Groups | Creating capturing and non-capturing group. | Python | Easy |
| Alternative Matching | Matching single regex out of several regex. | Python | Easy |
| Name | Preview | Code | Difficulty |
|---|---|---|---|
| Matching Same Text Again & Again | Match the same text as previously matched by the capturing group. | Python | Easy |
| Backreferences To Failed Groups | Backreference to a capturing group that match nothing. | Python | Easy |
| Branch Reset Groups | Alternatives having same capturing group | Perl | Easy |
| Forward References | Back reference to a group which appear later in regex. | Java | Easy |
| Name | Preview | Code | Difficulty |
|---|---|---|---|
| Positive Lookahead | A positive lookahead asserts the regex to match if the regexp ahead is matching. | Python | Easy |
| Negative Lookahead | It asserts the regex to match if regexp ahead is not matching. | Python | Easy |
| Positive Lookbehind | It asserts the regex to match if regexp behind is matching. | Python | Easy |
| Negative Lookbehind | It asserts the regex to match if regexp behind is not matching. | Python | Easy |
| Name | Preview | Code | Difficulty |
|---|---|---|---|
| Detect HTML links | Use Regular Expressions to detect links in a given HTML fragment. | Python | Medium |
| Detect HTML Tags | Given N lines of HTML source, print the HTML tags found within it. | Python | Easy |
| Find A Sub-Word | Use RegEx to count the number of times a sub-word appears in a given set of sentences. | Python | Easy |
| Alien Username | Validate the usernames from an alien planet. | Python | Easy |
| IP Address Validation | Validate possible IP Addresses with regex. | Python | Easy |
| Find a Word | Find a given word in a sentence using regex special characters. | Python | Medium |
| Detect the Email Addresses | Use Regular Expressions to detect the email addresses embedded in a given chunk of text. | Python | Medium |
| Detect the Domain Name | Use Regular Expressions to detect domain names from a chunk of HTML Markup provided to you. | Python | Medium |
| Building a Smart IDE: Identifying comments | A Text Processing Challenge. Identify the comments in program source codes. | Python | Medium |
| Detecting Valid Latitude and Longitude Pairs | Can you detect the Latitude and Longitude embedded in text snippets, using regular expressions? | Python | Easy |
| HackerRank Tweets | Write a regex to identify the tweets that has the string hackerrank in it | Python | Easy |
| Build a Stack Exchange Scraper | Use Regular Expression to Scrape Questions from Stack Exchange. | Python | Easy |
| Utopian Identification Number | Can you use regular expressions to check if the Utopian Identification Number is valid or not? | Python | Easy |
| Valid PAN format | Use regex to determine the validity of a given set of characters. | Python | Easy |
| Find HackerRank | Write a regex to find out if conversations start/end or both start and end with hackerrank | Python | Easy |
| Saying Hi | Use a regex to print all the lines that start with "hi " but are not immediately followed by a 'd' or 'D'. | Python | Easy |
| HackerRank Language | Use regex if an api request has a valid language string set or not | Python | Easy |
| Building a Smart IDE: Programming Language Detection | You are provided with a set of programs in Java, C and Python and you are also told which of the languages each program is in. Now, given a program written in one of these languages, can you identify which of the languages it is written in? | Python | Medium |
| Split the Phone Numbers | This problem introduces you to the concept of matching groups in regular expressions. | Python | Easy |
| Detect HTML Attributes | Use Regular Expressions to detect HTML Attributes corresponding to various tags. | Python | Easy |
| The British and American Style of Spelling | Use regular expression to find the count of a given word that ends with either ze or se | Python | Easy |
| UK and US: Part 2 | Use regular expression to count the number of occurrences of a given word with either our or or in it. | Python | Easy |