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digitalmars.D.learn - Int within ranges

reply nrgyzer <nrgyzer gmail.com> writes:
Hi there,

is there any possibility to get a sliced array from another array
between two ranges like:

int[uint] myArray;
myArray[10] = 1000;
myArray[20] = 2000;
myArray[30] = 3000;
myArray[40] = 4000;
myArray[50] = 5000;

int[] newArray = myArray[>= 20 .. <= 40]; // not able to do this
writeln(newArray); // should print [2000, 3000, 4000]

Is there any way to do this?
Jun 13 2011
next sibling parent reply "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Mon, 13 Jun 2011 12:15:40 -0400, nrgyzer <nrgyzer gmail.com> wrote:

 Hi there,

 is there any possibility to get a sliced array from another array
 between two ranges like:

 int[uint] myArray;
 myArray[10] = 1000;
 myArray[20] = 2000;
 myArray[30] = 3000;
 myArray[40] = 4000;
 myArray[50] = 5000;

 int[] newArray = myArray[>= 20 .. <= 40]; // not able to do this
 writeln(newArray); // should print [2000, 3000, 4000]

 Is there any way to do this?

import dcollections.TreeMap; auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[40] = 4000; myArray[50] = 5000; // this is a little kludgy, but necessary since you require <= 40 auto c = myArray.elemAt(40); c.popFront(); int newArray = array(myArray[20..c]); Note two things: 1. int[uint] is a hash, and so has no particular order. Therefore, there is no guarantee of iteration order, or that a range of such a container (if one existed) would be properly constructed with two keys. A TreeMap, or RedBlackTree, is sorted, and so the order is guaranteed. 2. dcollections.TreeMap is implemented with the same collection as std.container.RedBlackTree, so you could potentially do the same thing with it. But the dcollections.TreeMap API is more polished. -Steve
Jun 13 2011
next sibling parent bearophile < bearophileHUGS lycos.com> writes:
Steven Schveighoffer:

 But the dcollections.TreeMap API is more polished.

I think most people will want to use just Phobos, to avoid a dependency, even if the Phobos one is less polished... Bye, bearophile
Jun 13 2011
prev sibling parent reply nrgyzer <nrgyzer gmail.com> writes:
 On Mon, 13 Jun 2011 12:15:40 -0400, nrgyzer <nrgyzer gmail.com>

 Hi there,

 is there any possibility to get a sliced array from another array
 between two ranges like:

 int[uint] myArray;
 myArray[10] = 1000;
 myArray[20] = 2000;
 myArray[30] = 3000;
 myArray[40] = 4000;
 myArray[50] = 5000;

 int[] newArray = myArray[>= 20 .. <= 40]; // not able to do this
 writeln(newArray); // should print [2000, 3000, 4000]

 Is there any way to do this?

auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[40] = 4000; myArray[50] = 5000; // this is a little kludgy, but necessary since you require <= 40 auto c = myArray.elemAt(40); c.popFront(); int newArray = array(myArray[20..c]); Note two things: 1. int[uint] is a hash, and so has no particular order. Therefore,

 is no guarantee of iteration order, or that a range of such a

 (if one existed) would be properly constructed with two keys.  A

 or RedBlackTree, is sorted, and so the order is guaranteed.
 2. dcollections.TreeMap is implemented with the same collection as
 std.container.RedBlackTree, so you could potentially do the same

 with it.  But the dcollections.TreeMap API is more polished.
 -Steve

Exactly what I'm looking for, but how can I realize that it also gives me the elements when the key doesn't exists like: import std.range; import dcollections.TreeMap; auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[45] = 4500; myArray[50] = 5000; auto c = myArray.elemAt(40); c.popFront(); int[] newArray = array(myArray[20..c]); writeln(newArray); This will throw an exception because element 40 doesn't exist. Is there any possibility to get the element 20 and 30 from this map?
Jun 13 2011
parent reply nrgyzer <nrgyzer gmail.com> writes:
 On Mon, 13 Jun 2011 14:52:24 -0400, nrgyzer <nrgyzer gmail.com>

 On Mon, 13 Jun 2011 12:15:40 -0400, nrgyzer <nrgyzer gmail.com>

 Hi there,

 is there any possibility to get a sliced array from another




 between two ranges like:

 int[uint] myArray;
 myArray[10] = 1000;
 myArray[20] = 2000;
 myArray[30] = 3000;
 myArray[40] = 4000;
 myArray[50] = 5000;

 int[] newArray = myArray[>= 20 .. <= 40]; // not able to do




 writeln(newArray); // should print [2000, 3000, 4000]

 Is there any way to do this?

auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[40] = 4000; myArray[50] = 5000; // this is a little kludgy, but necessary since you require <= 40 auto c = myArray.elemAt(40); c.popFront(); int newArray = array(myArray[20..c]); Note two things: 1. int[uint] is a hash, and so has no particular order.



 there
 is no guarantee of iteration order, or that a range of such a

 (if one existed) would be properly constructed with two keys.  A

 or RedBlackTree, is sorted, and so the order is guaranteed.
 2. dcollections.TreeMap is implemented with the same collection



 std.container.RedBlackTree, so you could potentially do the same

 with it.  But the dcollections.TreeMap API is more polished.
 -Steve

Exactly what I'm looking for, but how can I realize that it also gives me the elements when the key doesn't exists like: import std.range; import dcollections.TreeMap; auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[45] = 4500; myArray[50] = 5000; auto c = myArray.elemAt(40); c.popFront(); int[] newArray = array(myArray[20..c]); writeln(newArray); This will throw an exception because element 40 doesn't exist. Is there any possibility to get the element 20 and 30 from this map?


 the place the element *would* be.
 When this code was first written, in order to detect whether elemAt

 your element, you compared it to container.end (similar to C++'s

 But now that cursors are tiny ranges, and have an empty property, I

 use that to indicate the element wasn't exactly found.  So I can

 the semantics to find the place the element *would* be.
 myArray[20..41];
 and it will find all elements >= 20 and < 41, regardless of whether

 41 were valid elements.
 Hm... can you post this as an enhancement to dcollections so it's

 forgotten?
 http://www.dsource.org/projects/dcollections/newticket
 -Steve

Thanks! I created a new ticket... by the way - is there any bug in DMD 2.053 by using my own opCmp? The following code throws me an HiddenFuncException: private import std.stdio : writeln; class Example { int pId; this(int id) { pId = id; } int opCmp(ref Example other) { return pId - other.pId; } } int main(string[] args) { Example[] exps; exps ~= new Example(1); exps ~= new Example(2); writeln(exps.sort); return 1; }
Jun 13 2011
parent nrgyzer <nrgyzer gmail.com> writes:
== Auszug aus Steven Schveighoffer (schveiguy yahoo.com)'s Artikel
 On Mon, 13 Jun 2011 15:44:01 -0400, nrgyzer <nrgyzer gmail.com>

 On Mon, 13 Jun 2011 14:52:24 -0400, nrgyzer <nrgyzer gmail.com>

 On Mon, 13 Jun 2011 12:15:40 -0400, nrgyzer





 wrote:
 Hi there,

 is there any possibility to get a sliced array from another




 between two ranges like:

 int[uint] myArray;
 myArray[10] = 1000;
 myArray[20] = 2000;
 myArray[30] = 3000;
 myArray[40] = 4000;
 myArray[50] = 5000;

 int[] newArray = myArray[>= 20 .. <= 40]; // not able to do




 writeln(newArray); // should print [2000, 3000, 4000]

 Is there any way to do this?

auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[40] = 4000; myArray[50] = 5000; // this is a little kludgy, but necessary since you require





 auto c = myArray.elemAt(40);
 c.popFront();
 int newArray = array(myArray[20..c]);
 Note two things:
 1. int[uint] is a hash, and so has no particular order.



 there
 is no guarantee of iteration order, or that a range of such a

 (if one existed) would be properly constructed with two





 TreeMap,
 or RedBlackTree, is sorted, and so the order is guaranteed.
 2. dcollections.TreeMap is implemented with the same





 as
 std.container.RedBlackTree, so you could potentially do the





 thing
 with it.  But the dcollections.TreeMap API is more polished.
 -Steve

Exactly what I'm looking for, but how can I realize that it




 gives me the elements when the key doesn't exists like:

 import std.range;
 import dcollections.TreeMap;

 auto myArray = new TreeMap!(uint, int);

 myArray[10] = 1000;
 myArray[20] = 2000;
 myArray[30] = 3000;
 myArray[45] = 4500;
 myArray[50] = 5000;

 auto c = myArray.elemAt(40);
 c.popFront();
 int[] newArray = array(myArray[20..c]);
 writeln(newArray);

 This will throw an exception because element 40 doesn't exist.




 there any possibility to get the element 20 and 30 from this




 It might be useful to have elemAt return an empty range that is

 the place the element *would* be.
 When this code was first written, in order to detect whether



 found
 your element, you compared it to container.end (similar to C++'s

 But now that cursors are tiny ranges, and have an empty



 can
 use that to indicate the element wasn't exactly found.  So I can

 the semantics to find the place the element *would* be.
 myArray[20..41];
 and it will find all elements >= 20 and < 41, regardless of



 20 and
 41 were valid elements.
 Hm... can you post this as an enhancement to dcollections so it's

 forgotten?
 http://www.dsource.org/projects/dcollections/newticket
 -Steve

Thanks! I created a new ticket... by the way - is there any bug in DMD 2.053 by using my own opCmp? The following code throws me an HiddenFuncException: private import std.stdio : writeln; class Example { int pId; this(int id) { pId = id; } int opCmp(ref Example other) {

int opCmp(Object other) Note, also, that ref is unnecessary, as all objects (i.e. class

 are passed by reference.
 -Steve

Works, thanks for all that!
Jun 13 2011
prev sibling next sibling parent "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Mon, 13 Jun 2011 13:25:39 -0400, bearophile <  
<bearophileHUGS lycos.com> wrote:

 Steven Schveighoffer:

 But the dcollections.TreeMap API is more polished.

I think most people will want to use just Phobos, to avoid a dependency, even if the Phobos one is less polished...

Sure, but it's difficult to demonstrate a possible solution without having the API for slicing present in the phobos version... Essentially, what I'm saying is it *could* be done in Phobos, if phobos' RedBlackTree was updated to be like dcollections'. -Steve
Jun 13 2011
prev sibling next sibling parent "Jonathan M Davis" <jmdavisProg gmx.com> writes:
On 2011-06-13 09:15, nrgyzer wrote:
 Hi there,
 
 is there any possibility to get a sliced array from another array
 between two ranges like:
 
 int[uint] myArray;
 myArray[10] = 1000;
 myArray[20] = 2000;
 myArray[30] = 3000;
 myArray[40] = 4000;
 myArray[50] = 5000;
 
 int[] newArray = myArray[>= 20 .. <= 40]; // not able to do this
 writeln(newArray); // should print [2000, 3000, 4000]
 
 Is there any way to do this?

Slices take a contiguous chunk of an array. You can't skip any values. So, if you want them separate, you're going to have to put them in another container yourself. - Jonathan M Davis
Jun 13 2011
prev sibling next sibling parent "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Mon, 13 Jun 2011 14:52:24 -0400, nrgyzer <nrgyzer gmail.com> wrote:

 On Mon, 13 Jun 2011 12:15:40 -0400, nrgyzer <nrgyzer gmail.com>

 Hi there,

 is there any possibility to get a sliced array from another array
 between two ranges like:

 int[uint] myArray;
 myArray[10] = 1000;
 myArray[20] = 2000;
 myArray[30] = 3000;
 myArray[40] = 4000;
 myArray[50] = 5000;

 int[] newArray = myArray[>= 20 .. <= 40]; // not able to do this
 writeln(newArray); // should print [2000, 3000, 4000]

 Is there any way to do this?

auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[40] = 4000; myArray[50] = 5000; // this is a little kludgy, but necessary since you require <= 40 auto c = myArray.elemAt(40); c.popFront(); int newArray = array(myArray[20..c]); Note two things: 1. int[uint] is a hash, and so has no particular order. Therefore,

 is no guarantee of iteration order, or that a range of such a

 (if one existed) would be properly constructed with two keys.  A

 or RedBlackTree, is sorted, and so the order is guaranteed.
 2. dcollections.TreeMap is implemented with the same collection as
 std.container.RedBlackTree, so you could potentially do the same

 with it.  But the dcollections.TreeMap API is more polished.
 -Steve

Exactly what I'm looking for, but how can I realize that it also gives me the elements when the key doesn't exists like: import std.range; import dcollections.TreeMap; auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[45] = 4500; myArray[50] = 5000; auto c = myArray.elemAt(40); c.popFront(); int[] newArray = array(myArray[20..c]); writeln(newArray); This will throw an exception because element 40 doesn't exist. Is there any possibility to get the element 20 and 30 from this map?

It might be useful to have elemAt return an empty range that is located at the place the element *would* be. When this code was first written, in order to detect whether elemAt found your element, you compared it to container.end (similar to C++'s STL). But now that cursors are tiny ranges, and have an empty property, I can use that to indicate the element wasn't exactly found. So I can change the semantics to find the place the element *would* be. myArray[20..41]; and it will find all elements >= 20 and < 41, regardless of whether 20 and 41 were valid elements. Hm... can you post this as an enhancement to dcollections so it's not forgotten? http://www.dsource.org/projects/dcollections/newticket -Steve
Jun 13 2011
prev sibling parent "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Mon, 13 Jun 2011 15:44:01 -0400, nrgyzer <nrgyzer gmail.com> wrote:

 On Mon, 13 Jun 2011 14:52:24 -0400, nrgyzer <nrgyzer gmail.com>

 On Mon, 13 Jun 2011 12:15:40 -0400, nrgyzer <nrgyzer gmail.com>

 Hi there,

 is there any possibility to get a sliced array from another




 between two ranges like:

 int[uint] myArray;
 myArray[10] = 1000;
 myArray[20] = 2000;
 myArray[30] = 3000;
 myArray[40] = 4000;
 myArray[50] = 5000;

 int[] newArray = myArray[>= 20 .. <= 40]; // not able to do




 writeln(newArray); // should print [2000, 3000, 4000]

 Is there any way to do this?

auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[40] = 4000; myArray[50] = 5000; // this is a little kludgy, but necessary since you require <= 40 auto c = myArray.elemAt(40); c.popFront(); int newArray = array(myArray[20..c]); Note two things: 1. int[uint] is a hash, and so has no particular order.



 there
 is no guarantee of iteration order, or that a range of such a

 (if one existed) would be properly constructed with two keys.  A

 or RedBlackTree, is sorted, and so the order is guaranteed.
 2. dcollections.TreeMap is implemented with the same collection



 std.container.RedBlackTree, so you could potentially do the same

 with it.  But the dcollections.TreeMap API is more polished.
 -Steve

Exactly what I'm looking for, but how can I realize that it also gives me the elements when the key doesn't exists like: import std.range; import dcollections.TreeMap; auto myArray = new TreeMap!(uint, int); myArray[10] = 1000; myArray[20] = 2000; myArray[30] = 3000; myArray[45] = 4500; myArray[50] = 5000; auto c = myArray.elemAt(40); c.popFront(); int[] newArray = array(myArray[20..c]); writeln(newArray); This will throw an exception because element 40 doesn't exist. Is there any possibility to get the element 20 and 30 from this map?


 the place the element *would* be.
 When this code was first written, in order to detect whether elemAt

 your element, you compared it to container.end (similar to C++'s

 But now that cursors are tiny ranges, and have an empty property, I

 use that to indicate the element wasn't exactly found.  So I can

 the semantics to find the place the element *would* be.
 myArray[20..41];
 and it will find all elements >= 20 and < 41, regardless of whether

 41 were valid elements.
 Hm... can you post this as an enhancement to dcollections so it's

 forgotten?
 http://www.dsource.org/projects/dcollections/newticket
 -Steve

Thanks! I created a new ticket... by the way - is there any bug in DMD 2.053 by using my own opCmp? The following code throws me an HiddenFuncException: private import std.stdio : writeln; class Example { int pId; this(int id) { pId = id; } int opCmp(ref Example other) {

The signature of this function must be int opCmp(Object other) Note, also, that ref is unnecessary, as all objects (i.e. class instances) are passed by reference. -Steve
Jun 13 2011