Algorithm 101: 3 Ways to Check if Two Sentences are Anagrams

#algorithm #javascript #anagram #beginners

6 0

Mar 13

Building upon our knowledge from word anagram and sentence palindrome, we will be looking at how to check for sentence anagram just as we promised while discussing word anagram


sentenceAnagram("McDonald's restaurants", "Uncle Sam's standard rot"); // true

sentenceAnagram("Church of Scientology", "rich-chosen goofy cult"); // true

Prerequisite

To benefit from this article, you need to have basic understanding of javascript's string, object and array methods.

Let's do this using:

toLowerCase(), map(), includes(), sort(), join()

      function sentenceAnagram(sentenceA, sentenceB) {
        let newSentenceA = sentenceA.toLowerCase();
        let newSentenceB = sentenceB.toLowerCase();
        let alphabet = "abcdefghijklmnopqrstuvwxyz";
        let numeric = "0123456789";
        let alphanumeric = [...alphabet, ...numeric];

        function createCharArray(sentence) {
          let charArray = [...sentence].map(char => {
            if (alphanumeric.includes(char)) {
              return char;
            }
          });

          return charArray.sort().join("");
        }

        charArrayA = createCharArray(newSentenceA);
        charArrayB = createCharArray(newSentenceB);

        return charArrayA === charArrayB;
      }

regular expression, toLowerCase(), forEach(), match(), sort(), push(), JSON.stringify()

      function sentenceAnagram(sentenceA, sentenceB) {
        let newSentenceA = sentenceA.toLowerCase();
        let newSentenceB = sentenceB.toLowerCase();
        let regEx = /\w/gi;

        function createCharArray(sentence) {
          let charArray = [];
          [...sentence].forEach(char => {
            if (char.match(regEx)) {
              charArray.push(char);
            }
          });

          return JSON.stringify(charArray.sort());
        }

        charArrayA = createCharArray(newSentenceA);
        charArrayB = createCharArray(newSentenceB);

        return charArrayA === charArrayB;
      }

toUpperCase(), toLowerCase(), forEach(), sort(), push(), hasOwnProperty(), JSON.stringify(), for...of...loop

      function sentenceAnagram(sentenceA, sentenceB) {
        let newSentenceA = sentenceA.toLowerCase();
        let newSentenceB = sentenceB.toLowerCase();

        function isDigit(char) {
          return char >= 0 && char <= 9;
        }

        function isLetter(char) {
          return char.toLowerCase() != char.toUpperCase();
        }

        function createCharObject(sentence) {
          let charObject = {};
          let charArray = [];

          // sanitize the sentence
          [...sentence].sort().forEach(char => {
            if (isDigit(char) || isLetter(char)) {
              charArray.push(char);
            }
          });

          let newCharArray = charArray
            .join("")
            .split(" ")
            .join("");

          // create an object of the array
          for (char of [...newCharArray]) {
            if (charObject.hasOwnProperty(char)) {
              charObject[char]++;
            } else {
              charObject[char] = 1;
            }
          }

          return JSON.stringify(charObject);
        }

        charArrayA = createCharObject(newSentenceA);
        charArrayB = createCharObject(newSentenceB);

        return charArrayA === charArrayB;
      }

Conclusion

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