Introduction to F# for the C# developer

F#
for the
C# developer
Nate Peterson
@njpetersonpa

Brief intro to F#
Thinking functionally
Look at some code

Simple vs. Complex
and
Familiar vs. Unfamiliar

F# is more than just a new language
It’s a new way of thinking

let add x y =
x + y
let add42 x =
add 42 x
add42 1

let add x y =
x + y
let add42 =
add 42
add42 1

public static class SumOfSquaresHelper
{
public static int Square(int i)
{
return i * i;
}
public static int SumOfSquares(int n)
{
int sum = 0;
for (int i = 1; i <= n; i++)
{
sum += Square(i);
}
return sum;
}
}

public static class FunctionalSumOfSquaresHelper
{
{
return Enumerable.Range(1, n)
.Select(i => i * i)
.Sum();
}
}

let square x = x * x
let sumOfSquares n =
[1..n] |>
List.map square|>
List.sum
sumOfSquares 100

Think about…
Concise – no noise
Simple vs. Complex
Familiar vs. Unfamiliar
where are the types
where’s the {}

public static class SumOfSquaresHelper
{
public static int Square(int i)
{
return i * i;
}
{
int sum = 0;
for (int i = 1; i <= n; i++)
{
if (i % 2 == 0)
{
sum += Square(i);
}
}
return sum;
}
}

public static class FunctionalSumOfSquaresHelper
{
{
return Enumerable.Range(1, n)
.Select(i => i * i)
.Where(i => i % 2 == 0)
.Sum();
}
}

let square x = x * x
let isEven x = x % 2 = 0
let sumOfSquares n =
[1..n] |>
List.filter
List.map square|>
List.filter isEven |>
List.sum
sumOfSquares 100

public List<string> Create()
{
var results = new List<string>();
for (var i = 0; i < 100; i++)
{
results.Add(FizzBuzz(i));
}
return results;
}
private static string FizzBuzz(int num)
{
if (num % 3 == 0 && num % 5 == 0)
{
return "FizzBuzz";
}
if (num % 3 == 0)
{
return "Fizz";
}
if (num % 5 == 0)
{
return "Buzz";
}
return num.ToString();
}

public List<string> Create(IEnumerable<int> sequence)
{
return Enumerable.Range(1, 100).Select(FizzBuzz).ToList();
}
private static string FizzBuzz(int num)
{
if (num % 3 == 0 && num % 5 == 0)
{
return "FizzBuzz";
}
if (num % 3 == 0)
{
return "Fizz";
}
if (num % 5 == 0)
{
return "Buzz";
}
return num.ToString();
}

Think about…
Concise – again
Pattern matching for flow control

public class Person
{
public Person(string firstName, string lastName)
{
}
}

public class Person
{
private string _firstName;
private string _lastName;
{
_firstName = firstName;
_lastName = lastName;
}
}

public class Person
{
{
}
public string FirstName
{
get
{
return _firstName;
}
}
}

public class Person
{
{
}
{
get
{
return _firstName;
}
}
public string LastName
{
get
{
return _lastName;
}
}
}

public class Person
{
private readonly string _firstName;
private readonly string _lastName;
{
}
{
get
{
return _firstName;
}
}
public string LastName
{
get
{
return _lastName;
}
}
}

type Person = {FirstName:string; LastName:string}
let nate = {FirstName=“Nate"; LastName=“Peterson"}

Introduction to F# for the C# developer

More Related Content

What's hot

Similar to Introduction to F# for the C# developer

Recently uploaded

Introduction to F# for the C# developer

Editor's Notes