Count characters in strings with or without string.slice

I am trying to learn how this problem has been solved but I am lost at string.slice(0,1) and i++ after that.

What is the need to use the slice method?

The questions is:

Write a function called countChars that accepts two parameters: a string and a character. This function should return a number representing the number of times that the character appears in string.

function countChars(string, character) {
    let count = 0;
    let i = 0;
    while (i < string.length) {
        if (string[i] === character) {
            count++;
        }
        string.slice(0, 1);
        i++;
    }
    return count;
}

Without slice

function countChars(string, character) {
    let count = 0;
    let i = 0;
    while (i < string.length) {
        if (string[i] === character) {
            count++;
        }
        i++;
    }
    return count;
}

console.log(countChars('foobar', 'o'))

Count of Substrings that can be formed without using the given list of , Given a string str and a list of characters L, the task is to count total numbers of substrings of the string str without using characters given in the list L. Examples: Explanation: On ignoring characters 'a' and 'b' from the given string, substring “ cd” is left. Function to find the Number of sub-strings. // without� console.log("Count", countChars("ABCDABC", "A")); string.slice(0, 1)The slicemethod extracts a section of a string and returns it as a new string, without modifying the original string. The return value is not used in this function, so you can remove the call.

Nina already solved it using your code, a shorter option would be using String.match

function countChars(string, character) {
  const { length } = string.match(new RegExp(character, 'ig')) || [];
  return length;
}

console.log(countChars('Foobar', 'o'));

7. Strings — How to Think Like a Computer Scientist: Learning with , The len function returns the number of characters in a string: The reason is that there is no 6th letter in "banana". is index < len(fruit), so when index is equal to the length of the string, the condition is false, and the body of the loop is not executed. The string module contains useful functions that manipulate strings. Online Character Count Tool. A while back I needed to count the amount of letters that a piece of text in an email template had (to avoid passing any character limits). Unfortunately, I could not think of a quick way to do so on my macbook and I therefore turned to the Internet.

Explanation of your code:

function countChars(string, character) {
    let count = 0; // set variable count to zero
    let i = 0; // set variable i to zero
    while (i < string.length) { // loop while i is less than lenght of string
        if (string[i] === character) { // check character at position i 
            count++; // Increment count by one
        }
        string.slice(0, 1); // returns the first character in string, but return value is not used. Can be removed
        i++; // increment variable i by one
    }
    return count; // returns count
}

console.log("Count", countChars("ABCDABC", "A"));

Count Occurrences of a Char in a String, Learn how to count characters with the core Java library and with libraries and frameworks such as Spring From no experience to actually building stuff. Using indexOf to Find All Occurrences of a Word in a String Quick intro to working with Strings with the Apache Commons library and StringUtils. Python Program to Count Total Characters in a String Example 1. This python program allows the user to enter a string. Next, it counts the total number of characters inside this string using For Loop.

If you're willing to look for other solutions, here is a short one.

function count(str, char){   

   let count = str.split('').filter(c => {
     return c.toLowerCase() === char.toLowerCase()
   });

  return count.length;
}

console.log(count('hello world', 'l'));

Note: The above solution is case-insensitive.

String.prototype.slice(), The slice() method extracts a section of a string and returns it as a new string, without modifying the original string. the length of str1 is 23. str2 = str1.slice(1, 8 ), str3 = str1.slice(4, -2), str4 = str1.slice(12), str5 = str1.slice(30);� The idea is to use two auxiliary arrays of size 256 (Assuming that characters are stored using 8 bits). Initialize all values in count [] as 0 and all values in index [] as n where n is length of string. Traverse the input string str and do following for every character c = str [i].

I would do it like this

function countChars(string, character) {
  return string.split('').filter(e => e === character).length;
}

console.log(countChars('foobar', 'o'))

But @bambam RegEx approach is likely the most efficient.

substr_count - Manual, substr_count — Count the number of substring occurrences. Description �. substr_count ( string $haystack , string $needle [, int $offset = 0 [, int $length ]] ) : int. substr_count() a simple version for an array needle (multiply sub-strings): < ?php Despite of the occurence of the character 'c' the pointer is not moved. up � down. In this article, we will discuss how to fetch the last N characters of a string in python. This N can be 1 or 4 etc. In python, a String is a sequence of characters, and each character in it has an index number associated with it.

3 ways to Count words in Java String, You can count words in Java String by using the split() method of String. A word is nothing but a non-space character in String, which is separated by one to count a number of words in given String in Java without using any of String utility and Algorithms (books); How to check if two given Strings are Anagram in Java ? Inspect verb is used to count or replace the characters in a string. String operations can be performed on alphanumeric, numeric, or alphabetic values. Inspect operations are performed from left to right. The options used for the string operations are as follows −

Python 3 Notes: Split and Join, on a specific substring 'x'. Without 'x' specified, .split() simply splits on all whitespace, as seen above. > But what if you want to split a string into a list of characters? In Python, characters are simply strings of length 1. The list() function turns a� In Julia, these are used to mark character objects, so 'a' is a character object, but "a" is a string with length 1. These are not equivalent. These are not equivalent. You can convert character objects to strings easily enough:

Ruby Strings Cheat Sheet, Ruby Strings cheat sheet of all shortcuts and commands. str.chop. Return a new string with last character removed from str # "string" => "strin". str.insert(index , str2). Insert str2 str.size. Return the character length of str (option 2). str.sum.

Comments
  • What did the slice method do? What happens if you don't use it?
  • it works fine even with slice, which is not necessary, because it does not change anything, because of a missing assingment.
  • A compact way to do what you want is to replace the content of the function with return string.split(character).length - 1;. See my answer for more information of your code and other examples, and why the code is buggy.
  • Doesn't work with characters outside of the BMP: console.log(countChars("😁😎😁", "😁"));
  • it seems not working with . character I guess :D. countChars('abc.devf.aa','.') returns 11 while expect 3
  • Since you need to escape regex special characters, that's true. @ducmai
  • A simpler, case-sensitive, slightly faster, no-need-to-escape-special-characters, Unicode-safe version: return string.split(character).length - 1; See my answer for more explanation and faster variants.
  • Hi! This doesn't work. split() only returns the input as one string. You could split it on an empty string with split('').