[HackerRank][Regex](java) Introduction

 

import java.util.regex.*;
...
Pattern.compile(Reg_Exp).matcher(Test_String).find();		// Java  ( Use \\ instead of using \ )

import re
str(bool(re.search(Regex_Pattern, Test_String))).lower()		# Python

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■  Matching Specific String

https://www.hackerrank.com/challenges/matching-specific-string/problem?isFullScreen=true 

Q.

You have a test string S. Your task is to match the string 'hackerrank'. This is case sensitive.

A.

(hackerrank)

hackerrank

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import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {    

    public static void main(String[] args) {
        
        Regex_Test tester = new Regex_Test();
        tester.checker("__________");  // Use '\\' instead of '\'.
    
    }
}

class Regex_Test {

    public void checker(String Regex_Pattern){
    
        Scanner Input = new Scanner(System.in);
        String Test_String = Input.nextLine();
        Pattern p = Pattern.compile(Regex_Pattern);
        Matcher m = p.matcher(Test_String);
        int Count = 0;
        while(m.find()){
            Count += 1;
        }
        System.out.format("Number of matches : %d",Count);
    }   
    
}

Regex_Pattern = r'_________'	# Do not delete 'r'.

import re

Test_String = input()

match = re.findall(Regex_Pattern, Test_String)

print("Number of matches :", len(match))

var Regex_Pattern = '_________';
//var Regex_Pattern = /_________/g;	//Do not delete `/` and `/g`.

function processData(Test_String) {
    //Enter your code here
    var Regex = new RegExp(Regex_Pattern, "g");
    var Array = Test_String.match(Regex);
    //var Array = Test_String.match(Regex_Pattern);
    console.log("Number of matches :", Array.length);
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});

 

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■  Matching Digits & Non-Digit Characters

https://www.hackerrank.com/challenges/matching-digits-non-digit-character/problem?isFullScreen=true 

Q.

You have a test string S. Your task is to match the pattern 'zzXzzXzzzz'
Here z denotes a digit character, and X denotes a non-digit character.

A.

\d{2}\D\d{2}\D\d{4}

 

ASCII	[0-9]	[^0-9]
Shorthand	\d	\D  =  [^\d]
Unicode	[\p{Nd}]	[^\p{Nd}]
Java	\p{Digit}	[^\p{Digit}]
POSIX	[:digit:]	[^[:digit:]]

 

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■  Matching Word & Non-Word Character

https://www.hackerrank.com/challenges/matching-word-non-word/problem?isFullScreen=true 

Q.

You have a test string S. Your task is to match the pattern 'zzzXzzzzzzzzzzXzzz'
Here z denotes any word character and X denotes any non-word character.

※  \w will match any word character.
  ( Word characters include alphanumeric characters (a-z, A-Z and 0-9) and underscores (_). )
※  \W matches any non-word character. 
  ( Non-word characters include characters other than alphanumeric characters (a-z, A-Z and 0-9) and underscore (_). )

A.

\w{3}\W\w{10}\W\w{3}

[A-Za-z0-9_]{3}[^A-Za-z0-9_][A-Za-z0-9_]{10}[^A-Za-z0-9_][A-Za-z0-9_]{3}

\p{IsWord}{3}[^\p{IsWord}]\p{IsWord}{10}[^\p{IsWord}]\p{IsWord}{3}

[\p{L}\p{Nl}\p{Nd}\p{Pc}]{3}[^\p{L}\p{Nl}\p{Nd}\p{Pc}][\p{L}\p{Nl}\p{Nd}\p{Pc}]{10}[^\p{L}\p{Nl}\p{Nd}\p{Pc}][\p{L}\p{Nl}\p{Nd}\p{Pc}]{3}

 

ASCII	[A-Za-z0-9_]	[^A-Za-z0-9_]
Shorthand	\w	\W  =  [^\w]
Unicode	[\p{L}\p{Nl}\p{Nd}\p{Pc}]	[^\p{L}\p{Nl}\p{Nd}\p{Pc}]
Java	\p{IsWord}	[^\p{IsWord}]
POSIX	[:word:]	[^[:word:]]

 

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■  Matching Whitespace & Non-Whitespace Character

https://www.hackerrank.com/challenges/matching-whitespace-non-whitespace-character/problem?isFullScreen=true 

Q.

You have a test string S. Your task is to match the pattern 'zzXzzXzz'
Here, z denotes whitespace characters, and X denotes non-white space characters.

※  \s matches any whitespace character [ \r\n\t\f ].
※  \S matches any non-white space character.

A.

\S{2}\s\S{2}\s\S{2}

 

ASCII	[ \t\r\n\v\f]	[^ \t\r\n\v\f]
Shorthand	\s	\S  =  [^\s]
Unicode	[\p{Z}\t\r\n\v\f]	[^\p{Z}\t\r\n\v\f]
Java	\p{Space}	[^\p{Space}]
POSIX	[:space:]	[^[:space:]]

 

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■  Matching Start & End

https://www.hackerrank.com/challenges/matching-start-end/problem?isFullScreen=true 

Q.

You have a test string S. Your task is to match the pattern 'Xzzzz.'
Here, Z denotes a word character, and X denotes a digit.
S must start with a digit X and end with . symbol.
S should be 6 characters long only.

A.

^\d\w{4}\.$

 

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■  Matching Anything But a Newline

https://www.hackerrank.com/challenges/matching-anything-but-new-line/problem?isFullScreen=true 

Q.

You have a test string S.
Your task is to write a regular expression that matches only and exactly strings of form:
'abc.def.ghi.jkx', where each variable a,b,c,d,e,f,g,h,i,j,k,x can be any single character except the newline.

※  The dot (.) matches anything (except for a newline).

A.

^.{3}\..{3}\..{3}\..{3}$

( 백슬래시 다음에 오는 문자가 특수문자일 경우 그 문자 자체를 의미  (ex) \. => .  )

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import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {    

    public static void main(String[] args) {
        
        Tester tester = new Tester();
        tester.check("________"); 
    
    }
}

class Tester {

    public void check(String pattern){
    
        Scanner scanner = new Scanner(System.in);
      	String testString = scanner.nextLine();
        Pattern p = Pattern.compile(pattern);
        Matcher m = p.matcher(testString);
        System.out.println(m.find());
        //System.out.format("%s", m.matches());
    }   
    
}

regex_pattern = r"_________"	# Do not delete 'r'.

import re
import sys

test_string = input()

match = re.match(regex_pattern, test_string) is not None

print(str(match).lower())
//print(str(bool(re.search(Regex_Pattern, input()))).lower())

var Regex_Pattern = /__________/g; //Do not delete '/' and 'g'. Replace __________ with your regex.

function processData(Test_String) {
    var matches = Test_String.match(Regex_Pattern);
    var match = matches != null && matches.length > 0;
    console.log(match);
    //console.log(!!Test_String.match(Regex_Pattern));
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input.trim();
});

process.stdin.on("end", function () {
   processData(_input);
});

 

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