### 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;

};
``````

#### 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
``````