Javascript
Get the last digit of a number
let number = 123
let lastDigit = number % 10; // return 3
let lastTwoDigits = number % 100 //return 23
Inserting dashes between odd and even numbers
function insertDashII(num) {
return String(num)
.replace(/([13579])(?=[13579])/g, "$1-")
.replace(/([2468])(?=[2468])/g, "$1*")
}
Replace every word not matching a pattern
function rakeGarden(garden) {
return garden.replace(/\w+/g,function(v){if(v!=='rock')v='gravel';return v;});
}
Make sure that every letter in a word is unique
function isIsogram(str){
return !/(\w).*\1/i.test(str)
}
Checking for Palindrome
const isPalindrome = (str) => str === reverse(str);
const reverse = (str) => str.toString().split('').reverse().join('');
Handling Pricing Combinations / Steps
The cost of deliveries is:
$3.85 for 40 newspapers $1.93 for 20 $0.97 for 10 $0.49 for 5 $0.10 for 1
Write a function that’s passed an integer representing the amount of newspapers and returns the cheapest price.
const cheapestQuote = newspapers => {
let total = 0;
total += Math.floor(newspapers/40) * 3.85;
newspapers %= 40;
total += Math.floor(newspapers/20) * 1.93;
newspapers %= 20;
total += Math.floor(newspapers/10) * 0.97;
newspapers %= 10;
total += Math.floor(newspapers/5) * 0.49;
newspapers %= 5;
total += newspapers * 0.1;
return total;
};
Using Regex format numbers as follows
addCommas(“$123”,regex) should return “$123” addCommas(“$1234”,regex) should return “$1,234” addCommas(“$12345”,regex) should return “$12,345” addCommas(“$1234567”,regex) should return “$1,234,567” addCommas(“$123456789”,regex) should return “$123,456,789”
var regex=/\d(?=(\d{3})+$)/g
const addCommas = (money,reg) => {
return money.replace(reg,x=>x+",") //like this
}
Check to see if a string is a natural number
const isInteger = (txt) => (/^-?\d+$/).test(txt);
Ruby
Getting value from a hash?
def what_is(x)
matches = {
42 => 'everything',
1 => 'one'
}
matches.default = 'nothing'
matches[x]
end
Get the first alphabetical word from an array
def getFirstWord(words)
words.min
end
Checking a value is within a range
def grader(score)
case score
when 0.6...0.7 then "D"
when 0.7...0.8 then "C"
when 0.8...0.9 then "B"
when 0.9..1 then "A"
else "F"
end
end
