Can You Explain this with an example.Encountered this when studying HOF in scala

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This is the Function.What are the arguments here?is it a function? and what is the return type?

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = ... 
 sumf

edited yesterday

asked yesterday

RAM SHANKER G

What sort of explanation are you looking for? You need to be a bit more specific about the problem you are facing.
– Tim
yesterday

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up vote
0
down vote

favorite

This is the Function.What are the arguments here?is it a function? and what is the return type?

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = ... 
 sumf

edited yesterday

asked yesterday

RAM SHANKER G

What sort of explanation are you looking for? You need to be a bit more specific about the problem you are facing.
– Tim
yesterday

add a comment |

up vote
0
down vote

favorite

This is the Function.What are the arguments here?is it a function? and what is the return type?

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = ... 
 sumf

edited yesterday

asked yesterday

RAM SHANKER G

This is the Function.What are the arguments here?is it a function? and what is the return type?

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = ... 
 sumf

scala higher-order-functions

edited yesterday

asked yesterday

RAM SHANKER G

edited yesterday

asked yesterday

RAM SHANKER G

edited yesterday

asked yesterday

RAM SHANKER G

asked yesterday

RAM SHANKER G

asked yesterday

RAM SHANKER G

What sort of explanation are you looking for? You need to be a bit more specific about the problem you are facing.
– Tim
yesterday

add a comment |

What sort of explanation are you looking for? You need to be a bit more specific about the problem you are facing.
– Tim
yesterday

What sort of explanation are you looking for? You need to be a bit more specific about the problem you are facing.
– Tim
yesterday

add a comment |

1 Answer
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oldest

votes

up vote
2
down vote

accepted

That is a function called sum. It takes as parameter one function from Int to Int and returns a function that when called with a pair of Ints returns another Int.

The actual result depends on the implementation, but we could for instance define it as:

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = 
 f(a) + f(b)
 
 sumf

Or simply:

def sum(f: Int => Int): (Int, Int) => Int = 
 (a: Int, b: Int) => f(a) + f(b)

In that case, you could call it like this for instance:

def f(a: Int): Int = a * a
def g(a: Int, b: Int): Int = sum(f)(a, b)
val x: Int = g(3, 4) // x = 25

edited yesterday

answered yesterday

houcros

398418

"That is a function called sum" – This is wrong. sum is not a function, it is a method. Functions and methods are fundamentally different in Scala: functions are objects, methods are not. (Methods belong to objects.) Methods can be generic, functions can't. Methods can have an implicit parameter list, functions can't. Methods can have optional parameters with default arguments, functions can't. Methods can have repeated parameters, functions can't.
– Jörg W Mittag
18 hours ago

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

up vote
2
down vote

accepted

That is a function called sum. It takes as parameter one function from Int to Int and returns a function that when called with a pair of Ints returns another Int.

The actual result depends on the implementation, but we could for instance define it as:

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = 
 f(a) + f(b)
 
 sumf

Or simply:

def sum(f: Int => Int): (Int, Int) => Int = 
 (a: Int, b: Int) => f(a) + f(b)

In that case, you could call it like this for instance:

def f(a: Int): Int = a * a
def g(a: Int, b: Int): Int = sum(f)(a, b)
val x: Int = g(3, 4) // x = 25

edited yesterday

answered yesterday

houcros

398418

"That is a function called sum" – This is wrong. sum is not a function, it is a method. Functions and methods are fundamentally different in Scala: functions are objects, methods are not. (Methods belong to objects.) Methods can be generic, functions can't. Methods can have an implicit parameter list, functions can't. Methods can have optional parameters with default arguments, functions can't. Methods can have repeated parameters, functions can't.
– Jörg W Mittag
18 hours ago

add a comment |

up vote
2
down vote

accepted

That is a function called sum. It takes as parameter one function from Int to Int and returns a function that when called with a pair of Ints returns another Int.

The actual result depends on the implementation, but we could for instance define it as:

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = 
 f(a) + f(b)
 
 sumf

Or simply:

def sum(f: Int => Int): (Int, Int) => Int = 
 (a: Int, b: Int) => f(a) + f(b)

In that case, you could call it like this for instance:

def f(a: Int): Int = a * a
def g(a: Int, b: Int): Int = sum(f)(a, b)
val x: Int = g(3, 4) // x = 25

edited yesterday

answered yesterday

houcros

398418

"That is a function called sum" – This is wrong. sum is not a function, it is a method. Functions and methods are fundamentally different in Scala: functions are objects, methods are not. (Methods belong to objects.) Methods can be generic, functions can't. Methods can have an implicit parameter list, functions can't. Methods can have optional parameters with default arguments, functions can't. Methods can have repeated parameters, functions can't.
– Jörg W Mittag
18 hours ago

add a comment |

up vote
2
down vote

accepted

That is a function called sum. It takes as parameter one function from Int to Int and returns a function that when called with a pair of Ints returns another Int.

The actual result depends on the implementation, but we could for instance define it as:

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = 
 f(a) + f(b)
 
 sumf

Or simply:

def sum(f: Int => Int): (Int, Int) => Int = 
 (a: Int, b: Int) => f(a) + f(b)

In that case, you could call it like this for instance:

def f(a: Int): Int = a * a
def g(a: Int, b: Int): Int = sum(f)(a, b)
val x: Int = g(3, 4) // x = 25

edited yesterday

answered yesterday

houcros

398418

That is a function called sum. It takes as parameter one function from Int to Int and returns a function that when called with a pair of Ints returns another Int.

The actual result depends on the implementation, but we could for instance define it as:

def sum(f: Int => Int): (Int, Int) => Int = 
 def sumf(a: Int, b: Int): Int = 
 f(a) + f(b)
 
 sumf

Or simply:

def sum(f: Int => Int): (Int, Int) => Int = 
 (a: Int, b: Int) => f(a) + f(b)

In that case, you could call it like this for instance:

def f(a: Int): Int = a * a
def g(a: Int, b: Int): Int = sum(f)(a, b)
val x: Int = g(3, 4) // x = 25

edited yesterday

answered yesterday

houcros

398418

edited yesterday

answered yesterday

houcros

398418

answered yesterday

houcros

398418

answered yesterday

houcros

398418

"That is a function called sum" – This is wrong. sum is not a function, it is a method. Functions and methods are fundamentally different in Scala: functions are objects, methods are not. (Methods belong to objects.) Methods can be generic, functions can't. Methods can have an implicit parameter list, functions can't. Methods can have optional parameters with default arguments, functions can't. Methods can have repeated parameters, functions can't.
– Jörg W Mittag
18 hours ago

add a comment |

"That is a function called sum" – This is wrong. sum is not a function, it is a method. Functions and methods are fundamentally different in Scala: functions are objects, methods are not. (Methods belong to objects.) Methods can be generic, functions can't. Methods can have an implicit parameter list, functions can't. Methods can have optional parameters with default arguments, functions can't. Methods can have repeated parameters, functions can't.
– Jörg W Mittag
18 hours ago

"That is a function called sum" – This is wrong. sum is not a function, it is a method. Functions and methods are fundamentally different in Scala: functions are objects, methods are not. (Methods belong to objects.) Methods can be generic, functions can't. Methods can have an implicit parameter list, functions can't. Methods can have optional parameters with default arguments, functions can't. Methods can have repeated parameters, functions can't.
– Jörg W Mittag
18 hours ago

add a comment |

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