Defining my own concat

concatenate synonym
concatenation programming
concatenation definition
how to pronounce concatenate
concatenate meaning in hindi
concatenate excel
concatenation in a sentence
concatenation math

I'm reading a book and it asked me to define my own concat function. I defined it correctly here:

concat :: [[a]] -> [a]
concat [] = []
-- concat [[]] = []
concat (xs:xss) = xs ++ (Main.concat xss)

I have two questions about this.

  1. Why don't I need that line I commented out?
  2. When I call this with Main.concat [[]], step by step, how is it evaluated? The way I think about it, it goes into the 2nd definition, but I can't make sense of that. If I'm right and it goes to the 2nd definition, what are the values of xs and xss?

If I'm right and it goes to the 2nd definition, what are the values of xs and xss?

Let's ask:

> f (xs:xss) = (xs, xss)
> f [[]]

So now try substituting these values into your definition:

concat (xs:xss) = xs ++ (Main.concat xss)
                = [] ++ (Main.concat [] )
                = [] ++ []
                = []

Concatenate, Concatenate definition is - linked together. How to use concatenate in a sentence​. "Catenate," a verb in its own right meaning "to link in a series," had also arrived on the scene by the early 17th Listen to Our Podcast about concatenate​. "Concatenate" has a somewhat longer history as an adjective, meaning "linked together," than as a verb. The adjective first appeared in English in the 15th century and the verb was in use by the early 17th century. "Catenate," a verb in its own right meaning "to link in a series," had also arrived on the scene by the early 17th century.

[[]] can also be written as [] : [] (using the (:) constructor) -- that is, the list whose head is the empty list and whose tail is the empty list. So this can successfully pattern match against xs:xss.

So after matching xs with [] and xss with [], we effectively get the following behavior:

let xs = [] in
  let xss = [] in
    xs ++ (Main.concat xss)

And with substitution, we get

[] ++ (Main.concat [])

That recursive call will hit the base case and thus return [], giving [] ++ [] and eventually [].

Excel Formulas: Using CONCATENATE to Combine Names, Use the Excel CONCATENATE function to practice combining names in your Each person has his or her own row, and there are columns for each person's first Before we start writing the function, we'll need to insert a new column in our​  Concatenation means joining two values or two strings together, similar to excel we use & or also known as ampersand operator to concatenate, two concatenate two strings we use & operator like String 1 & String 2, now there is an important thing to remember and that is while using the & operator we need to provide spaces or VBA will consider it as long.

TL/DR: [[]] = [] : [] just as [1] = 1 : [], so it matches the x:xs pattern.

In Haskell a list is defined as so:

data [a]    -- a list of `a`s is...
  = []      -- an empty list...
  | a : [a] -- or an `a`, then a list of `a`s.

When we write [1,2,3], this is just syntactic sugar for 1 : (2 : (3 : [])), and since : is what we call right-associative, we can also just write 1:2:3:[].

For this reason there are only two cases that are normally required when pattern matching on lists: [] and (x:xs). [] is obviously the empty list, and (x:xs) is a non-empty list, where x is the first element and xs is the rest of the list.

Let's examine that definition, ignoring the commented line. I've removed some unnecessary brackets, by the way:

concat :: [[a]] -> [a]
concat []     = []                  -- The empty list case
concat (x:xs) = x ++ Main.concat xs -- The nonempty list case

We see that you've actually covered all the cases: this is now defined for all lists, so at least in theory the case concat [[]] = [] is redundant.

In practice this is also true, because concat [[]] = [] ++ concat [] = [] anyway, which falls into the second line's case, since [[]] = [] : [] which matches the (x:xs) pattern.

What is Concatenate?, Computer dictionary definition of what concatenate means, including related links​, information, and terms. In programming languages, an operator is used to denote concatenation. For example, In the my $name = "Nathan"; print "Hello " . Logic to concatenate two strings. Concatenation of two strings is simple copying a string to another. To concatenate two strings str1 and str2, you will copy all characters of str2 at the end of str1. Below is the step by step descriptive logic to concatenate two string. Input two string from user.

Best way to concatenate #define to "string", Best way to concatenate #define to "string" My only question is there a more graceful way of performing this and something that wont produce warnings? Or​, you can build your own function to do what you want, and then  When you define your own Python function, it works just the same. From somewhere in your code, you’ll call your Python function and program execution will transfer to the body of code that makes up the function. Note: In this case, you will know where the code is and exactly how it works because you wrote it!

How to concatenate answers from 2 questions to define choices?, Never mind - I resolved my own problem by having two separate select_one lists - one for common name and one for scientific name - and then  xda-developers Samsung Galaxy S7 Samsung Galaxy S7 Questions & Answers Defining relationships for my own contact by schlockbock XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality.

Concatenation -- from Wolfram MathWorld, Thus the concatenation of the strings "book" and "case" is the string etc., is well​-defined. The concatenation of two or more numbers is the number formed by concatenating their numerals. Hints help you try the next step on your own. Create a new workbook or open the workbook in which you want to use your newly created User Defined Function (UDF). Open the Visual Basic Editor which is built into Microsoft Excel by going to Tools->Macro->Visual Basic Editor (or pressing Alt+F11). Add a new Module to your workbook by clicking in the button shown.

  • hint: [] ++ [] == []
  • Hint 2: [x1,x2,x3,x4,...,xn] = x1 : x2 : x3 : x4 : ... : xn : []