FreeCodeCamp/HelpJavaScript

Get help on our basic JavaScript and Algorithms Challenges. If you are posting code that is large use Gist - https://gist.github.com/ paste the link here.

Ahmed Ramy

@Shadilix

um shouldnt that code be like
num = 5
then
i = 5
then what happens in the loop is
543*2?

Saif Ur Rahman

@saifsmailbox98

5 * 5 * 4 * 3 * 2

kumquatfelafel

@kumquatfelafel

@Shadilix num is already 5, so this happens ^^^

Ahmed Ramy

@Shadilix

function factorialize(num) {
  if (num === 0)
    {
      return 1;
    }
  for (var i = num -1 ; i >=2 ; i--)
    {
      num *= i;
    }
  return num;
}

factorialize(1);

that worked ! :D

Stephen James

@sjames1958gm

@Shadilix :+1:

Saif Ur Rahman

@saifsmailbox98

:+1:

Ahmed Ramy

@Shadilix

thanks !!!!
@saifsmailbox98 @saifsmailbox98 @kumquatfelafel

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kumquatfelafel

@kumquatfelafel

@Shadilix what you can also do is create another variable to store the product. That way, you can go up or down with ease without modifying num.

Ahmed Ramy

@Shadilix

how so ?

@sjames1958gm thanks !

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kumquatfelafel

@kumquatfelafel

@Shadilix you'd just have something like...

function factorialize(num) {
  var factorial =1;
  for (var i = 2; i <= num ; i++)
  {
      factorial *= i;
  }
  return factorial;
}

Ahmed Ramy

@Shadilix

oh , i tried that but for some reason it didnt work ...

hold on i'll try it again before going for the next challenge

Roxroy

@roxroy

@kysnazz , you can round the number to 2 decimal places
console.log( ( 0.6*6).toFixed(2) ) // OutPut 3.60

CamperBot

@camperbot

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Ahmed Ramy

@Shadilix

@kumquatfelafel

function factorialize(num) {
  var factorial = 1;
  for (var i =2 ; i <= num ; i++)
    {
      factorial = num*i;
    }
  return factorial;
}

it doesnt work

Nick Cleary

@Hijerboa

'''

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@camperbot

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Saif Ur Rahman

@saifsmailbox98

@Shadilix https://repl.it/JEp6/0

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Nick Cleary

@Hijerboa

can someone tell me why my code isn't working?

function palindrome(str) {
  str.toLowerCase();
  var workingString = str.replace(/[`~!@#$%^&*()_|+\-=?;:'",.<>\{\}\[\]\\\/]/gi, '');
  var splitup = workingString.split("");
  var reversed = splitup.reverse();
  var joined = reversed.join("");
  var newString = joined;
  if(newString === str){
    return true;
  } else {
    return false;
  }

}

It works for anything without special characters

kumquatfelafel

@kumquatfelafel

@Hijerboa I would avoid having something like that in your replace function. Take a closer look at what's available for regex https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions

Nick Cleary

@Hijerboa

I tried something like .replace(/[^\w\s]/gi, '') which should replace all special characters will null I believe but that didn't work either

Coy Sanders

@coymeetsworld

\w includes whitespace

http://regexr.com/ can test out regex here

kumquatfelafel

@kumquatfelafel

@Hijerboa One thing I will say is that strings are immutable. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLowerCase
As a result, your toLowerCase actually does not change your original string, but returns a new string that you do nothing with.

Moisés Man

@moigithub

\w includes _
soo that regex will KEEP _ @Hijerboa and spaces

Nick Cleary

@Hijerboa

@kumquatfelafel so I should make an new variable with the toLowerCase, like I did with the replace?

@moigithub ah ok thank you

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kumquatfelafel

@kumquatfelafel

@Hijerboa You don't necessarily need to create a new variable for everything you do. You can also chain your functions or reassign into old variables.

Saif Ur Rahman

@saifsmailbox98

@Hijerboa you are comparing with str, it contains non-alphanumeric characters.

reverse() changes the original array.

toLowerCase() only returns the lowercased vaue.

kumquatfelafel

@kumquatfelafel

For example, since toLowerCase returns a string, you can actually call it then call replace on that returned string immediately afterwards.
str = str.toLowerCase().replace(blahblahblah);

Nick Cleary

@Hijerboa

function palindrome(str) {
  var newString = str.toLowerCase().replace(/[^a-z]/gi, '').split("").reverse().join();
  if(newString === str){
    return true;
  } else {
    return false;
  }

}

this is my new code and it isn't working. I chained the expressions like you said @kumquatfelafel

Saif Ur Rahman

@saifsmailbox98

@Hijerboa [^a-z0-9]

kumquatfelafel

@kumquatfelafel

^. You want to keep numbers as well.

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