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112 Create skeleton for regex #118

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tboychuk merged 5 commits into main from 112-crazy-regex-exercise
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67 changes: 67 additions & 0 deletions 3-0-java-core/3-6-3-crazy-regex/README.MD
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# <img src="https://raw.githubusercontent.com/bobocode-projects/resources/master/image/logo_transparent_background.png" height=50/>Crazy Regex

### Pre-conditions ❗
You're supposed to know how to work regex and be able to build Patterns and Matchers
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Objectives mean the learning goals of this exercise. What you specified here is prerequisites


### Objectives
* **build Patterns to extract** necessary parts from text ✅
* **manipulate** extracted text with **Matcher** object ✅

### Regular expressions - sequence of characters that define a search pattern for text

---

There 2 peace pf puzzle:
* Literal characters - I want to match literally the character I specified (like 'a')
* Meta characters - I want to match any character of this kind (more generic/abstract thing)

Single char

* \\d -> 0-9
* \\D -> negate of \\d
* \\w -> A-Za-z0-9
* \\W -> negate of \\w
* \\s -> whitespace, tab
* \\S -> negate of \\s
* . -> anything but newline
* \\. -> literal dot


Quantifiers - modify single characters how many of them you want match in a row
* \* -> Occurs zero or more times
* \+ -> 1 or more
* ? -> zero or one
* {min, max} -> some range
* {n} -> precise quantity


Position
* ^ -> beginning
* $ -> end
* \\b -> word boundary

---

Character class -> is the thing that appears in between []. For example [abc] -> match 'a' or 'b' or 'c'.
Another example [-.] -> match dash or period. Here . is not meta character anymore and ^ are special characters inside []
* [0-5] -> match all numbers from 0 to 5. [^0-5] -> match anything that NOT 0-5
BUT it works like meta character only when it on first position, otherwise - its literal, [a^bc] - like this

---

Capturing Groups - whenever u do regex search it matches whole result as a group 0.
* \\d{3}-\\d{3}-\\d{4} -> 212-555-1234 = GROUP 0

Parentheses can capture a subgroup:
\\d{3}-(\\d{3})-(\\d{4}) where 212-555-1234 = GROUP 0, 555 = GROUP 1, 1234 = GROUP 2

We can refer to this groups by 1ドル ($ when we want to replace) and 1円 (within regex itself referring to capture group
it's called back reference)

---

#### 🆕 First time here? – [See Introduction](https://github.com/bobocode-projects/java-fundamentals-course/tree/main/0-0-intro#introduction)
#### ➡️ Have any feedback? – [Please fill the form ](https://forms.gle/jhXEAzG4TB81S43CA)



19 changes: 19 additions & 0 deletions 3-0-java-core/3-6-3-crazy-regex/pom.xml
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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>3-0-java-core</artifactId>
<groupId>com.bobocode</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

<artifactId>3-6-3-crazy-regex</artifactId>

<properties>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>

</project>
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package com.bobocode.se;

import com.bobocode.util.ExerciseNotCompletedException;

import java.util.regex.Pattern;

/**
* {@link CrazyRegex} is an exercise class. Each method returns Pattern class which
* should be created using regex expression. Every method that is not implemented yet
* throws {@link ExerciseNotCompletedException}
* @author Andriy Paliychuk
* TODO: remove exception and implement each method of this class using java.util.regex.Pattern
*/
public class CrazyRegex {

/**
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@Meitoseshifu every javadoc starts from Create Pattern that accepts String with regex inside and can * find which makes it redundant. You can simplify it, e.g. A pattern that finds a specific word.

* A Pattern that that finds all words "Curiosity" in text
*
* @return a pattern that looks for the word "Curiosity"
*/
public Pattern findSpecificWord() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds first word in text
*
* @return a pattern that looks for the first word in text
*/
public Pattern findFirstWord() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds last word in text
*
* @return a pattern that looks for the last word in text
*/
public Pattern findLastWord() {
throw new ExerciseNotCompletedException();
}

/**
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@Meitoseshifu I believe it makes sense to provide some examples inside javadoc. A text and then what should be the result if you use this pattern to find the matches. In this method, I wasn't sure what means "all numbers". E.g. if I have in the text 25th of October then should "25" be found or not? It can be explained in the example.

* A Pattern that finds all numbers in text. When we have "555-555", "(555)555" and "30th" in text
* our pattern must grab all that numbers:
* "555" - four times, and one "30"
*
* @return a pattern that looks for numbers
*/
public Pattern findAllNumbers() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds all dates. For instance: "1971年11月23日"
*
* @return a pattern that looks for dates
*/
public Pattern findDates() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds different variations of word "color".
* We are looking for: "color", "colour", "colors", "colours"
*
* @return a pattern that looks for different variations of word "color"
*/
public Pattern findDifferentSpellingsOfColor() {
throw new ExerciseNotCompletedException();
}

/**
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@Meitoseshifu since it's not necessarily clear what is a zip code, it would be nice to have an example here as well.

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Or at least explanation: "a zip code is a 5-digit number without any characters or special symbols,"

* A Pattern that finds all zip codes in text.
* Zip code is a 5-digit number without any characters or special symbols.
* For example: 72300
*
* @return a pattern that looks for zip codes
*/
public Pattern findZipCodes() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds different variations of word "link".
* We are looking for: "lynk", "link", "l nk", "l(nk"
*
* @return a pattern that looks for different variations of word "link"
*/
public Pattern findDifferentSpellingsOfLink() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds phone numbers.
* For example: "555-555-5555"
*
* @return a pattern that looks for phone numbers
*/
public Pattern findSimplePhoneNumber() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds numbers with following requirements:
* - inside the number can be only digits from 0 to 5
* - length 3
*
* @return a pattern that looks for numbers with length 3 and digits from 0 to 5 in the middle
*/
public Pattern findNumbersFromZeroToFiveWithLengthThree() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds all words in text that have length 5
*
* @return a pattern that looks for the words that have length 5
*/
public Pattern findAllWordsWithFiveLength() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds words and numbers with following constraints:
* - not shorter than two symbols
* - not longer than three symbols
*
* @return a pattern that looks for words and numbers that not shorter 2 and not longer 3
*/
public Pattern findAllLettersAndDigitsWithLengthThree() {
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@Meitoseshifu method name does not correspond to the description.

throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds all words that begin with capital letter
*
* @return a pattern that looks for the words that begin with capital letter
*/
public Pattern findAllWordsWhichBeginWithCapitalLetter() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds only the following abbreviation:
* - AK, AL, AR, AZ, CA, CO, CT, PR, PA, PD
*
* @return a pattern that looks for the abbreviations above
*/
public Pattern findAbbreviation() {
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@Meitoseshifu maybe instead of writing Pattern.compile("THIS IS WHAT REALLY MATTERS") we can change the exercise so every method returns a regex String? What do you think?

throw new ExerciseNotCompletedException();
}

/**
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It would be good to have an example.

* A Pattern that finds all open braces
*
* @return a pattern that looks for all open braces
*/
public Pattern findAllOpenBraces() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds everything inside []
*
* @return a pattern that looks for everything inside []
*/
public Pattern findOnlyResources() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds all https links in note.txt
*
* @return a pattern that looks for all https links in note.txt
*/
public Pattern findOnlyLinksInNote() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds all http links in nasa.json
*
* @return a pattern that looks for all http links in nasa.json
*/
public Pattern findOnlyLinksInJson() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds all .com, .net and .edu emails
*
* @return a pattern that looks for all .com, .net and .edu emails
*/
public Pattern findAllEmails() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds the following examples of phone numbers:
* - 555-555-5555
* - 555.555.5555
* - (555)555-5555
*
* @return a pattern that looks for phone numbers patterns above
*/
public Pattern findAllPatternsForPhoneNumbers() {
throw new ExerciseNotCompletedException();
}

/**
* A Pattern that finds only duplicates
*
* @return a pattern that looks for duplicates
*/
public Pattern findOnlyDuplicates() {
throw new ExerciseNotCompletedException();
}

/**
* You have a text where all names recorded as first name, last name.
* Create matcher and use method replaceAll to record that names as:
* - last name first name
*
* @return String where all names recorded as last name first name
*/
public String replaceFirstAndLastNames(String names) {
throw new ExerciseNotCompletedException();
}

/**
* You have a text with phone numbers.
* Create matcher and use method replaceAll to replace last digits:
* - 555-XXX-XXXX
*
* @return String where in all phone numbers last 7 digits replaced to X
*/
public String replaceLastSevenDigitsOfPhoneNumberToX(String phones) {
throw new ExerciseNotCompletedException();
}

/**
* You have a text with resources and links to those resources:
* - [Bobocode](https://www.bobocode.com)
* Create matcher and use method replaceAll to get the following result:
* - <a href="https://www.bobocode.com">Bobocode</a>
*
* @return String where all resources embraced in href
*/
public String insertLinksAndResourcesIntoHref(String links) {
throw new ExerciseNotCompletedException();
}


}
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