Làm cách nào để tìm các ký tự lặp lại trong một chuỗi trong JavaScript?
Chúng tôi được yêu cầu viết một hàm JavaScript nhận vào một chuỗi và trả về một chuỗi mới chỉ chứa các từ xuất hiện nhiều lần trong chuỗi ban đầu Show Ví dụ. Nếu chuỗi đầu vào là - const str = "big black bug bit a big black dog on his big black nose"; Sau đó, đầu ra phải là - const output = "big black"; Thí dụHãy viết mã cho chức năng này - const str = "big black bug bit a big black dog on his big black nose"; const findDuplicateWords = str => { const strArr = str.split(" "); const res = []; for(let i = 0; i < strArr.length; i++){ if(strArr.indexOf(strArr[i]) !== strArr.lastIndexOf(strArr[i])){ if(!res.includes(strArr[i])){ res.push(strArr[i]); }; }; }; return res.join(" "); }; console.log(findDuplicateWords(str)); đầu raĐầu ra trong bảng điều khiển. - big black Trong bài viết này, chúng ta được cung cấp một chuỗi, nhiệm vụ của chúng ta là tìm sự xuất hiện của một ký tự trong chuỗi với sự trợ giúp của một hàm do người dùng định nghĩa. Example: Input : "hello" Output : h occur 1 times e occur 1 times l occur 2 times o occur 1 times Explanation : here "hello" have 1 h, so it have 1 value. as same e have 1, l have 2 , o have 1. Example 2: Input : "did" Output: d occur 2 times i occur 1 times Cách tiếp cận 1. Theo cách tiếp cận này, chúng tôi sử dụng cấu trúc dữ liệu bản đồ để lưu trữ số lần các ký tự xuất hiện
Thí dụ. Ví dụ này cho thấy việc sử dụng phương pháp được giải thích ở trên Javascript
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______3 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times4 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times8 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times0 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3
g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3
g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times9
h occur 1 times e occur 1 times l occur 2 times o occur 1 times2
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______3 h occur 1 times e occur 1 times l occur 2 times o occur 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______1
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 2h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 4
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 0h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 2
g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______133_______4 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______133_______6 //function to print occurrence of character 7h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 1 2 3h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 5 6h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 function 0h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 function 4h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 function 6function 7 function 8h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times3 printans( ans ) 1h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times1 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times1 printans( ans ) 5h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7_______5_______00 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3
g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times09
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times15 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times16 đầu ra h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times Cách tiếp cận 2. Trong cách tiếp cận này, chúng tôi sử dụng vòng lặp for lồng nhau để lặp qua chuỗi và đếm cho từng ký tự trong chuỗi.
Thí dụ. Ví dụ này cho thấy việc sử dụng phương pháp được giải thích ở trên Javascript
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times19
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times22
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______26 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______133_______6 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times29 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 1h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times34 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times35 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 5 6h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______42 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______3 h occur 1 times e occur 1 times l occur 2 times o occur 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2_______5_______1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times49 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times51 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times3 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times54 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times1 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times1 //function to print occurrence of character 6h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times59 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times62_______5_______63 6g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times1 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times1 //function to print occurrence of character 6h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times69 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times1 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times1
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times73 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times1 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 //function to print occurrence of character 6h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times80 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7_______5_______82 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times7 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times2 g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3
g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times3
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times09
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times97 h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times16 đầu ra g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times Cách tiếp cận-3. Trong cách tiếp cận này, chúng tôi sẽ sử dụng vòng lặp for để lặp qua chính chuỗi hoàn chỉnh. Đây là cách tiếp cận đơn giản nhất mà chúng tôi có thể thực hiện để tìm ra nhiệm vụ kết quả Làm cách nào để tìm các từ lặp lại trong một chuỗi trong JavaScript?Để làm điều đó, hãy sử dụng chuỗi. . tách dấu chấm câu khỏi chuỗi với. thay thế() thay đổi tất cả ký tự thành chữ thường với. toLowerCase() chuyển đổi chuỗi thành mảng từ với. tách ra() lặp qua từng từ (. forEach ), thêm nó vào một đối tượng đếm từ Làm cách nào để tìm các ký tự lặp lại trong một mảng trong JavaScript?Tìm các giá trị trùng lặp trong một mảng bằng javaScript . Sử dụng phương thức indexOf() Sử dụng phương thức has() Sử dụng một cặp đối tượng & giá trị khóa Sử dụng chức năng "một số" Sử dụng phép lặp Làm cách nào để kiểm tra xem chuỗi có chứa cùng một ký tự trong JavaScript không?Bạn có thể kiểm tra xem chuỗi JavaScript có chứa ký tự hoặc cụm từ hay không bằng cách sử dụng phương thức include(), indexOf() hoặc biểu thức chính quy . bao gồm () là phương pháp phổ biến nhất để kiểm tra xem một chuỗi có chứa một chữ cái hoặc một loạt các chữ cái hay không và được thiết kế riêng cho mục đích đó. |