HackerRank Regex Substitution solution in Python

YASH PAL,

HackerRank Regex Substitution solution in Python – In this Hackerrank Regex substitution problem in Python programming. The re.sub() tool (sub stands for substitution) evaluates a pattern and, for each valid match, it calls a method (or lambda).
The method is called for all matches and can be used to modify strings in different ways.
The re.sub() method returns the modified string as an output.

Learn more about re.sub().

Transformation of Strings

Code

import re

#Squaring numbers
def square(match):
    number = int(match.group(0))
    return str(number**2)

print re.sub(r"\d+", square, "1 2 3 4 5 6 7 8 9")

Output

1 4 9 16 25 36 49 64 81


Replacements in Strings

Code

import re

html = """
<head>
<title>HTML</title>
</head>
<object type="application/x-flash" 
  data="your-file.swf" 
  width="0" height="0">
  <!-- <param name="movie"  value="your-file.swf" /> -->
  <param name="quality" value="high"/>
</object>
"""

print re.sub("(<!--.*?-->)", "", html) #remove comment

Output

<head>
<title>HTML</title>
</head>
<object type="application/x-flash" 
  data="your-file.swf" 
  width="0" height="0">

  <param name="quality" value="high"/>
</object>

Task

You are given a text of N lines. The text contains && and || symbols.
Your task is to modify those symbols to the following:

&& → and
|| → or

Both && and || should have a space ” ” on both sides

HackerRank Regex Substitution solution in python

Hackerrank Regex Substitution problem solution in Python 2.

import re

n = int(raw_input())
for _ in range(0, n):
    line = raw_input()
    line = re.sub(r' [&]{2,2} ', ' and ', line)
    line = re.sub(r' [|]{2,2} ', ' or ', line)
    line = re.sub(r' [&]{2,2} ', ' and ', line)
    line = re.sub(r' [|]{2,2} ', ' or ', line)
    print(line)

Regex Substitution problem solution in Python 3.

import re

ii = int(input())

for i in range(0,ii):
   txt = input()
   txt = re.sub(r" && "," and ",txt)
   txt = re.sub(r" || "," or ",txt)
   txt = re.sub(r" && "," and ",txt)
   txt = re.sub(r" || "," or ",txt)
   print(txt)

Problem solution in pypy programming.

# Enter your code here. Read input from STDIN. Print output to STDOUT
import sys
import re

pat = re.compile(r'''(?<= )(&&|||)(?= )''', re.U|re.I|re.M|re.S)

for idx in range(int(raw_input())):
    l = raw_input()
    if pat.search(l):
        print(pat.sub(lambda m: 'and' if m.group(1) =='&&' else 'or', l))
    else:
        print(l)

Problem solution in pypy3 programming.

import re 

for _ in range(int(input())):
    str_ = input()
    str_ = re.sub(r"(?<= )(&&)(?= )", "and", str_)
    print(re.sub(r"(?<= )(||)(?= )", "or", str_))

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