How to add a single item to an array
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Never heard of it until you asked - so I had to look at wikipedia.
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
As the Wikipedia article says: "In nearly all versions of APL, it is theoretically possible to express any computable function in one expression, that is, in one line of code" - the one-liner Game of Life is an excellent example. I learned APL as early as 1975-76, on one of the worlds earliest "PCs", the IBM 5100 - APL was almost exclusively an IBM thing then - and it was a well known joke that IBM was working on writing the entire OS360 (the first operating system for the 360/370 mainframe series) in a single line of APL :-) There are still elements of APL that I miss, in particular the "workspace" concept: You do your stuff in a sandpit where you throw in functions, variables and whatever stuff, and throw them out when no longer needed - while the "program" (workspace) running. On the 5100, you could save the entire workspace on disk in its current state, or you could declare selected variables as persistent. There were file system operations, but you rarely needed it. There have been languages with similar concepts (I believe Smalltalk comes close), but mainline programming 40 years later still are based on concepts that could be compared to "Of course you have to tell how much space to reserve for a file before starting to use it" (that's essentially how IBMs mainframe file systems were at the time). APL was so much more flexible and dynamic... I'm getting carried away. Maybe I tonight should curl up in my recliner in front of my fireplace with the old APL book, memorizing what the world was like when I was a youngster...
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As the Wikipedia article says: "In nearly all versions of APL, it is theoretically possible to express any computable function in one expression, that is, in one line of code" - the one-liner Game of Life is an excellent example. I learned APL as early as 1975-76, on one of the worlds earliest "PCs", the IBM 5100 - APL was almost exclusively an IBM thing then - and it was a well known joke that IBM was working on writing the entire OS360 (the first operating system for the 360/370 mainframe series) in a single line of APL :-) There are still elements of APL that I miss, in particular the "workspace" concept: You do your stuff in a sandpit where you throw in functions, variables and whatever stuff, and throw them out when no longer needed - while the "program" (workspace) running. On the 5100, you could save the entire workspace on disk in its current state, or you could declare selected variables as persistent. There were file system operations, but you rarely needed it. There have been languages with similar concepts (I believe Smalltalk comes close), but mainline programming 40 years later still are based on concepts that could be compared to "Of course you have to tell how much space to reserve for a file before starting to use it" (that's essentially how IBMs mainframe file systems were at the time). APL was so much more flexible and dynamic... I'm getting carried away. Maybe I tonight should curl up in my recliner in front of my fireplace with the old APL book, memorizing what the world was like when I was a youngster...
370 is one of those numbers where, if you cube the digits and add the results, it comes out to the original number. 3 x 3 x 3 = 27 7 x 7 x 7 = 343 0 x 0 x 0 = 0 27 + 343 + 0 = 370 (I worked for I've Been Moved from 1979-1987) :)
Cheers, Mike Fidler "I intend to live forever - so far, so good." Steven Wright "I almost had a psychic girlfriend but she left me before we met." Also Steven Wright "I'm addicted to placebos. I could quit, but it wouldn't matter." Steven Wright yet again.
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could be worse ...
string[] oldarray = { "A", "B", "C" };
string newitem = "D";
oldarray = (String.Join(",", oldarray) + "," + newitem).Split(',');Consult your mental health professional immediately! ;)
Cheers, Mike Fidler "I intend to live forever - so far, so good." Steven Wright "I almost had a psychic girlfriend but she left me before we met." Also Steven Wright "I'm addicted to placebos. I could quit, but it wouldn't matter." Steven Wright yet again.
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370 is one of those numbers where, if you cube the digits and add the results, it comes out to the original number. 3 x 3 x 3 = 27 7 x 7 x 7 = 343 0 x 0 x 0 = 0 27 + 343 + 0 = 370 (I worked for I've Been Moved from 1979-1987) :)
Cheers, Mike Fidler "I intend to live forever - so far, so good." Steven Wright "I almost had a psychic girlfriend but she left me before we met." Also Steven Wright "I'm addicted to placebos. I could quit, but it wouldn't matter." Steven Wright yet again.
MikeTheFid wrote:
(I worked for I've Been Moved from 1979-1987)
So maybe you can confirm (or deny) what I've been told: An icon used in the 360 series marketing was a full circle, with one vertical radius drawn, like in a tradional "on/off" toggle button. Then I have heard said that the icon chosen for the 370 series was a bigger circle :-) People telling this story illustrate the new icon: A double circle, not consentric but touching where the radius crosses the rim. I can't remember ever seing this symbol in officiall IBM documentation, but maybe it was before I got into computing. (And, my only experience with IBM mainframes is for a single student project, on a remote machine I never saw.) Maybe this was an internal joke within IBM. Or maybe outside IBM. As we say where I live: If it isn't the truth, it sure is a great lie! ... I think it is so great that I sort of wish that it is true :-)
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List ccList = new List();
ccList.Add(cc);
foo.Items = ccList.ToArray();- Create a list.
- Add the item to the list.
- Convert the list to an array.
:sigh:
Latest Article - Code Review - What You Can Learn From a Single Line of Code
Learning to code with python is like learning to swim with those little arm floaties. It gives you undeserved confidence and will eventually drown you. - DangerBunny
Artificial intelligence is the only remedy for natural stupidity. - CDP1802
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How come nobody came up with the one line solution :rolleyes: ?
foo.items = new List() { cc }.ToArray();
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
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I think a better subject would be: How to create an array with a single item I thought this was going to be some sort of array concatenation/insertion N^3 algorithm.
Exactly. Something that actually answers the original question - like this:
int\[\] existingArray = { 1, 12, 123, 1234 }; existingArray = existingArray.Concat(new\[\] { 12345 }).ToArray(); -
List ccList = new List();
ccList.Add(cc);
foo.Items = ccList.ToArray();- Create a list.
- Add the item to the list.
- Convert the list to an array.
:sigh:
Latest Article - Code Review - What You Can Learn From a Single Line of Code
Learning to code with python is like learning to swim with those little arm floaties. It gives you undeserved confidence and will eventually drown you. - DangerBunny
Artificial intelligence is the only remedy for natural stupidity. - CDP1802
Adding a single item to an array causes the entire array to be reallocated and copied. Simply put, the only array that can add an item is a linked list. Some of the suggested solutions use a different datatype List<> to create a copy of the original array, use its built in function ".Add" to insert an item, then creating a brand new array containing all the items. If the array needs to change again, then a whole new copy will be created in memory. This is all okay because it works, but it's not ideal. Copying a large array over and over only to add a single item at the end repeatedly will consume more CPU cycles (electricity and time) than necessary. Do what you have to to make it work, but then search for a better approach and adopt that when you find it. The highest performance method would be to use a linked list. In C++, linked lists can be very fast & cheap, but there are also some implementations in C#. The List<> object is a very nice implementation of a linked list, but there is also a LinkedList<> object that is optimized for adding items anywhere within the object.
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How come nobody came up with the one line solution :rolleyes: ?
foo.items = new List() { cc }.ToArray();
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
var array = new[] { item }; -
As the Wikipedia article says: "In nearly all versions of APL, it is theoretically possible to express any computable function in one expression, that is, in one line of code" - the one-liner Game of Life is an excellent example. I learned APL as early as 1975-76, on one of the worlds earliest "PCs", the IBM 5100 - APL was almost exclusively an IBM thing then - and it was a well known joke that IBM was working on writing the entire OS360 (the first operating system for the 360/370 mainframe series) in a single line of APL :-) There are still elements of APL that I miss, in particular the "workspace" concept: You do your stuff in a sandpit where you throw in functions, variables and whatever stuff, and throw them out when no longer needed - while the "program" (workspace) running. On the 5100, you could save the entire workspace on disk in its current state, or you could declare selected variables as persistent. There were file system operations, but you rarely needed it. There have been languages with similar concepts (I believe Smalltalk comes close), but mainline programming 40 years later still are based on concepts that could be compared to "Of course you have to tell how much space to reserve for a file before starting to use it" (that's essentially how IBMs mainframe file systems were at the time). APL was so much more flexible and dynamic... I'm getting carried away. Maybe I tonight should curl up in my recliner in front of my fireplace with the old APL book, memorizing what the world was like when I was a youngster...
"You can always tell an APL programmer, but not much."
User: Technical term used by developers. See Idiot.
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List ccList = new List();
ccList.Add(cc);
foo.Items = ccList.ToArray();- Create a list.
- Add the item to the list.
- Convert the list to an array.
:sigh:
Latest Article - Code Review - What You Can Learn From a Single Line of Code
Learning to code with python is like learning to swim with those little arm floaties. It gives you undeserved confidence and will eventually drown you. - DangerBunny
Artificial intelligence is the only remedy for natural stupidity. - CDP1802
If you think that's bad you should seen how I've seen multiple items get added to an array which the pseudo code was pretty much Create new array that's one item bigger than the old array Copy everything from the old array into the new one Add one item to the slightly larger array.(The new array is now full) repeat the previous 3 lines until you're done adding however many items you need to add. Yes, I've literally seen that done in C++ and damn is it inefficient. (Slow and fragments memory like crazy.)
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MikeTheFid wrote:
(I worked for I've Been Moved from 1979-1987)
So maybe you can confirm (or deny) what I've been told: An icon used in the 360 series marketing was a full circle, with one vertical radius drawn, like in a tradional "on/off" toggle button. Then I have heard said that the icon chosen for the 370 series was a bigger circle :-) People telling this story illustrate the new icon: A double circle, not consentric but touching where the radius crosses the rim. I can't remember ever seing this symbol in officiall IBM documentation, but maybe it was before I got into computing. (And, my only experience with IBM mainframes is for a single student project, on a remote machine I never saw.) Maybe this was an internal joke within IBM. Or maybe outside IBM. As we say where I live: If it isn't the truth, it sure is a great lie! ... I think it is so great that I sort of wish that it is true :-)
[IBM System/360 retrospective](https://it.toolbox.com/blogs/williamfavero/the-ibm-the-ibm-system-360-it-started-it-all-50-years-ago-today-and-the-world-has-never-been-the-same-since-040814) Near the bottom...
Cheers, Mike Fidler "I intend to live forever - so far, so good." Steven Wright "I almost had a psychic girlfriend but she left me before we met." Also Steven Wright "I'm addicted to placebos. I could quit, but it wouldn't matter." Steven Wright yet again.
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Adding a single item to an array causes the entire array to be reallocated and copied. Simply put, the only array that can add an item is a linked list. Some of the suggested solutions use a different datatype List<> to create a copy of the original array, use its built in function ".Add" to insert an item, then creating a brand new array containing all the items. If the array needs to change again, then a whole new copy will be created in memory. This is all okay because it works, but it's not ideal. Copying a large array over and over only to add a single item at the end repeatedly will consume more CPU cycles (electricity and time) than necessary. Do what you have to to make it work, but then search for a better approach and adopt that when you find it. The highest performance method would be to use a linked list. In C++, linked lists can be very fast & cheap, but there are also some implementations in C#. The List<> object is a very nice implementation of a linked list, but there is also a LinkedList<> object that is optimized for adding items anywhere within the object.
Since you're mentioning C++, you should be aware that the implementation of std::vector is clever enough to reallocate only occasionally, making it almost as fast as std::list for the purpose of repeated adding of elements to the end. It's only the insertion of elements in the mid or at the front that always requires a reallocation. Of course there are always people who still manage to mess it up anyway...
GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)
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MikeTheFid wrote:
(I worked for I've Been Moved from 1979-1987)
So maybe you can confirm (or deny) what I've been told: An icon used in the 360 series marketing was a full circle, with one vertical radius drawn, like in a tradional "on/off" toggle button. Then I have heard said that the icon chosen for the 370 series was a bigger circle :-) People telling this story illustrate the new icon: A double circle, not consentric but touching where the radius crosses the rim. I can't remember ever seing this symbol in officiall IBM documentation, but maybe it was before I got into computing. (And, my only experience with IBM mainframes is for a single student project, on a remote machine I never saw.) Maybe this was an internal joke within IBM. Or maybe outside IBM. As we say where I live: If it isn't the truth, it sure is a great lie! ... I think it is so great that I sort of wish that it is true :-)
I was reading IBM 360 software documentation in the 1960s. (There were multiple operating systems for the 360 series because OS360 was nowhere near being released.) The logo on the documents I read was the face of a simple compass. The paper these documents were printed on was lighter than newsprint. I never did get my Fortran program to work ...
-
List ccList = new List();
ccList.Add(cc);
foo.Items = ccList.ToArray();- Create a list.
- Add the item to the list.
- Convert the list to an array.
:sigh:
Latest Article - Code Review - What You Can Learn From a Single Line of Code
Learning to code with python is like learning to swim with those little arm floaties. It gives you undeserved confidence and will eventually drown you. - DangerBunny
Artificial intelligence is the only remedy for natural stupidity. - CDP1802
The solution is to avoid using arrays whenever possible, even if there is not immediate need to add items to the collection after it's been populated the first time. Even when I'm using results from the Fileinfo or DirectoryInfo objects, I store the results in a list instead of the array they return.
".45 ACP - because shooting twice is just silly" - JSOP, 2010
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You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
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When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013 -
As the Wikipedia article says: "In nearly all versions of APL, it is theoretically possible to express any computable function in one expression, that is, in one line of code" - the one-liner Game of Life is an excellent example. I learned APL as early as 1975-76, on one of the worlds earliest "PCs", the IBM 5100 - APL was almost exclusively an IBM thing then - and it was a well known joke that IBM was working on writing the entire OS360 (the first operating system for the 360/370 mainframe series) in a single line of APL :-) There are still elements of APL that I miss, in particular the "workspace" concept: You do your stuff in a sandpit where you throw in functions, variables and whatever stuff, and throw them out when no longer needed - while the "program" (workspace) running. On the 5100, you could save the entire workspace on disk in its current state, or you could declare selected variables as persistent. There were file system operations, but you rarely needed it. There have been languages with similar concepts (I believe Smalltalk comes close), but mainline programming 40 years later still are based on concepts that could be compared to "Of course you have to tell how much space to reserve for a file before starting to use it" (that's essentially how IBMs mainframe file systems were at the time). APL was so much more flexible and dynamic... I'm getting carried away. Maybe I tonight should curl up in my recliner in front of my fireplace with the old APL book, memorizing what the world was like when I was a youngster...
You are correct, Smalltalk images do work similarly, but there is a risk implied, as discussed by Gilad Bracha in Room 101... [Room 101: An Image Problem](https://gbracha.blogspot.co.uk/2009/10/image-problem.html)
"If you don't fail at least 90 percent of the time, you're not aiming high enough." Alan Kay.