1596485520
Algorithms: Calculating Combination with Ruby
Background
When I learned to code, I hadn’t slept in a math classroom in 14 years.
I studied philosophy and taught courses on Symbolic Logic. I can talk about deductive proofs for days, but when people pull out a f of n’s… x²…_ [insert Greek letter] — _I nod along, but trust me, I have no idea what’s happening.
For this reason, I got a huge boost of empowerment when I figured out an algorithm question asking, “How can you determine the mathematical combination (nCr) of two numbers?”
If you’re like ‘what the…?’, then hell yeah, you are me a day ago. Let’s go!
The Meat
Defining the Problem
I’ll try my best to explain a combination:
Imagine you’re losing a high stakes poker game. You have sweat on your neck as a couple Mafia grunts stare daggers at you. As the big one cracks his knuckles, you think “It’s a shame I never learned to count cards. But maybe start now?”
Your mind is racing. You start thinking, how do I start? How many possible hands are there in the deck? Well, there are 52 cards. You get 5 distinct cards in each hand, and they can come in any order. Let’s see, some quick math in your head and…
Yeah, the answer is not obvious. But, you’re attempting a combination. A combination is when you have a collection of items and you want to find all the possible selections from that collection — for example, every possible hand from a deck of cards.
By the way, the answer is 2,598,960. Each hand has a 1/2,598,960th chance of being drawn. With numbers that big, it’s good we can train a computer to solve the problem.
#ruby #combination #ruby-on-rails #algorithms #dev #algorithms
What is GEEK
Buddha Community
1596485520
Algorithms: Calculating Combination with Ruby
Background
When I learned to code, I hadn’t slept in a math classroom in 14 years.
I studied philosophy and taught courses on Symbolic Logic. I can talk about deductive proofs for days, but when people pull out a f of n’s… x²…_ [insert Greek letter] — _I nod along, but trust me, I have no idea what’s happening.
For this reason, I got a huge boost of empowerment when I figured out an algorithm question asking, “How can you determine the mathematical combination (nCr) of two numbers?”
If you’re like ‘what the…?’, then hell yeah, you are me a day ago. Let’s go!
The Meat
Defining the Problem
I’ll try my best to explain a combination:
Imagine you’re losing a high stakes poker game. You have sweat on your neck as a couple Mafia grunts stare daggers at you. As the big one cracks his knuckles, you think “It’s a shame I never learned to count cards. But maybe start now?”
Your mind is racing. You start thinking, how do I start? How many possible hands are there in the deck? Well, there are 52 cards. You get 5 distinct cards in each hand, and they can come in any order. Let’s see, some quick math in your head and…
Yeah, the answer is not obvious. But, you’re attempting a combination. A combination is when you have a collection of items and you want to find all the possible selections from that collection — for example, every possible hand from a deck of cards.
By the way, the answer is 2,598,960. Each hand has a 1/2,598,960th chance of being drawn. With numbers that big, it’s good we can train a computer to solve the problem.
#ruby #combination #ruby-on-rails #algorithms #dev #algorithms
1622462142
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1626850869
7 Reasons to Trust Ruby on Rails
Ruby on Rails is an amazing web development framework. Known for its adaptability, it powers 3,903,258 sites internationally. Ruby on Rails development speeds up the interaction within web applications. It is productive to such an extent that a Ruby on Rails developer can develop an application 25% to 40% quicker when contrasted with different frameworks.
Around 2.1% (21,034) of the best 1 million sites utilize Ruby on Rails. The framework is perfect for creating web applications in every industry. Regardless of whether it's medical services or vehicles, Rails carries a higher degree of dynamism to each application.
Be that as it may, what makes the framework so mainstream? Some say that it is affordable, some say it is on the grounds that the Ruby on Rails improvement environment is simple and basic. There are numerous reasons that make it ideal for creating dynamic applications.
Read more: Best Ruby on Rails projects Examples
7 reasons Ruby on Rails is preferred
There are a few other well-known backend services for web applications like Django, Flask, Laravel, and that's only the tip of the iceberg. So for what reason should organizations pick Ruby on Rails application development? We believe the accompanying reasons will feature why different organizations trust the framework -
Quick prototyping
Rails works on building MVPs in a couple of months. Organizations incline toward Ruby on Rails quick application development as it offers them more opportunity to showcase the elements. Regular development groups accomplish 25% to 40% higher efficiency when working with Rails. Joined with agile, Ruby on Rails empowers timely delivery.
Basic and simple
Ruby on Rails is easy to arrange and work with. It is not difficult to learn also. Both of these things are conceivable as a result of Ruby. The programming language has one of the most straightforward sentence structures, which is like the English language. Ruby is a universally useful programming language, working on things for web applications.
Cost-effective
Probably the greatest advantage of Rails is that it is very reasonable. The system is open-source, which implies there is no licensing charge included. Aside from that, engineers are additionally effectively accessible, that too at a lower cost. There are a large number of Ruby on Rails engineers for hire at an average compensation of $107,381 each year.
Startup-friendly
Ruby on Rails is regularly known as "the startup technology." It offers adaptable, fast, and dynamic web improvement to new companies. Most arising organizations and new businesses lean toward this as a direct result of its quick application improvement capacities. It prompts quicker MVP development, which permits new companies to rapidly search for venture investment.
Adaptable framework
Ruby on Rails is profoundly adaptable and versatile. In any event, when engineers miss adding any functions, they can utilize different modules to add highlights into the application. Aside from that, they can likewise reclassify components by eliminating or adding them during the development environment. Indeed, even individual projects can be extended and changed.
Convention over configuration
Regardless of whether it's Ruby on Rails enterprise application development or ecommerce-centered applications, the system utilizes convention over configuration. Developers don't have to go through hours attempting to set up the Ruby on Rails improvement environment. The standard conventions cover everything, improving on things for engineers on the task. The framework likewise utilizes the standard of "Don't Repeat Yourself" to guarantee there are no redundancies.
Versatile applications
At the point when organizations scale, applications regularly slack. However, this isn't the situation with Ruby on Rails web application development. The system powers sites with high traffic, It can deal with a huge load of worker demands immediately. Adaptability empowers new businesses to keep utilizing the structure even after they prepare their first model for dispatch.
Bottom Line
Ruby on Rails is as yet a significant framework utilized by organizations all over the world - of every kind. In this day and age, it is probably the best framework to digitize endeavors through powerful web applications.
A software development company provides comprehensive Ruby on Rails development to guarantee startups and MNCs can benefit as much as possible from their digital application needs.
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#ruby on rails development #ruby on rails application development #ruby on rails web application development #ruby on rails developer
1594674000
Day 14 of 30 Ruby Coding Challenge - Fibonacci Sequence the Ruby Way
Day 14 of 30. We’re going to solve the famous Fibonacci sequence in a more Ruby Way, which will be much better (hopefully!) than the previous solution
Hey friends!
This is the blog post version of the Youtube video from the 30 Ruby Coding Challenges in 30 Days series
Fibonacci Sequence
It’s time to organize the kitchen and to get a better code design to solve the Fibonacci Sequence, which was the previous coding challenge:
We want to calculate the first N numbers in a Fibonacci sequence
This was the last coding solution:
Ruby
def fibonacci(count)
n1 = 0
n2 = 1
sequence = [n1, n2]
while count > 2
# sum of the previous 2 numbers
n3 = n1 + n2
sequence.push(n3)
# assigning the new numbers to calculate the next number in the sequence
n1 = n2
n2 = n3
count = count - 1
end
return sequence
end
puts fibonacci(8)
# 0 1 1 2 3 5 8 13
```
You can be honest, it's not that great.
## The Ruby Way to Solve the Fibonacci Problem
### **Step 1**
Ruby allows us to go from one number to another in a sequence like this:
Ruby
```
(0..10).each do |number|
end
In our example we want to avoid the count mutation (fancy name for change). We can do that by the following code:
Ruby
(0…count).each do |number|
end
```
That’s great because Ruby will **automatically iterate over the array**
### **Step 2**
A better way to store the number in the sequence would be:
Ruby
```
sequence << number if number <= 1
sequence << sequence[-1] + sequence[-2] if sequence.length >= 2
The complete code, a little bit leaner with a better strategy, would be:
Ruby
def fibonacci(count)
sequence = []
(0…count).each do |number|
sequence << number if number <= 1
sequence << sequence[-1] + sequence[-2] if sequence.length >= 2
end
sequence
end
```
Fantastic! Ruby deals with the problem really well!#ruby #programming #coding #ruby on rails #algorithm #fibonacci #tutorial for beginners #algorithm analysis #coding basics #coding challenges
1594449660
Day 16 of 30 Ruby Coding Challenge - Sum Even Numbers
DZone > Web Dev Zone > Day 16 of 30 Ruby Coding Challenge - Sum Even Numbers in a Fibonacci Sequence
Day 16 of 30 Ruby Coding Challenge - Sum Even Numbers in a Fibonacci Sequence
Hey friends!
This is the blog post version of the Youtube video from the 30 Ruby Coding Challenges in 30 Days series
We’ve solved the Fibonacci sequence here, here and here, which means that we have some clues of how to create a Fibonacci sequence :)
Today we want to be a little bit daring by solving the following problem:
I want to sum all even numbers in a Fibonacci sequence
Fibonacci Sequence in Ruby
As you already know, this is one of the solutions:
Ruby
1
def fibonacci_sum(count)
2
number = 0
3
sequence = []
4
(0..count).each do |item|
5
number = item if item <= 1
6
number = sequence[-1] + sequence[-2] if item > 1
7
sequence << number
8
end
9
sequence
10
end
We’re returning a Fibonacci sequence, however, that’s not what we’re looking for
Sum Even Numbers in a Fibonacci Sequence in Ruby
We’re going to:
- add a local variable called sum
- then update this variable only if the number is even
- return the sum variable
Ruby
1
def fibonacci_sum(count)
2
sum = 0
3
number = 0
4
sequence = []
5
(0..count).each do |item|
6
number = item if item <= 1
7
number = sequence[-1] + sequence[-2] if item > 1
8
sequence << number
9
10
sum += number if number % 2 == 0
11
end
12
sum
13
end
#ruby #programming #coding #ruby on rails #algorithm #challenges #tutorial for beginners #algorithm analysis #coding basics