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digitalmars.D.learn - Are there an equivalent to C#'s List in D's stdlib?

reply Jack <jckj33 gmail.com> writes:
I coduln't find an equivalent in the documentation, I could see 
appender, Array, container etc but none of has a Remove(T item) 

have to write one myself or I just couldn't find?

[1]: 
https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1.remove?view=net-5.0
Jan 07 2021
next sibling parent reply James Blachly <james.blachly gmail.com> writes:
On 1/7/21 9:53 PM, Jack wrote:

 I coduln't find an equivalent in the documentation, I could see 
 appender, Array, container etc but none of has a Remove(T item) method 

 one myself or I just couldn't find?
 
 [1]: 
 https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1
remove?view=net-5.0 
 


Speaking for me personally, I would try to work with Ranges[0], and in a 
functional style simply filter [1] out in the same way one calls 


for example:

```D-ish
auto someRangeType = functionThatDoesWhatever();

auto rangeWithItemRemoved = someRangeType.filter(x => x.prop != whatever);
```


`Equals` such that the call to `Remove(new Part(){PartId=1534, 
PartName="cogs"});` considers only the PartId and does not match on name.

Again, you could `filter(x => x.PartId != 1534)`, or you could, as in 

comparing, then `filter(x => x != new Part(1534, "cogs"))`

Finally, although you asked about the standard library, there are many 
other container libraries, like emsi-containers [2] which do have List 


[0] http://ddili.org/ders/d.en/ranges.html
[1] https://dlang.org/phobos/std_algorithm_iteration.html#filter
[2] https://dlang-community.github.io/containers/index.html
Jan 07 2021
parent reply Jack <jckj33 gmail.com> writes:
On Friday, 8 January 2021 at 03:06:24 UTC, James Blachly wrote:

 On 1/7/21 9:53 PM, Jack wrote:

 I coduln't find an equivalent in the documentation, I could 
 see appender, Array, container etc but none of has a Remove(T 

 and I do have to write one myself or I just couldn't find?
 
 [1]: 
 https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1.remove?view=net-5.0
 


 Speaking for me personally, I would try to work with Ranges[0], 
 and in a functional style simply filter [1] out in the same way 


 for example:

 ```D-ish
 auto someRangeType = functionThatDoesWhatever();

 auto rangeWithItemRemoved = someRangeType.filter(x => x.prop != 
 whatever);
 ```


 overloaded `Equals` such that the call to `Remove(new 
 Part(){PartId=1534, PartName="cogs"});` considers only the 
 PartId and does not match on name.

 Again, you could `filter(x => x.PartId != 1534)`, or you could, 

 you are comparing, then `filter(x => x != new Part(1534, 
 "cogs"))`

 Finally, although you asked about the standard library, there 
 are many other container libraries, like emsi-containers [2] 
 which do have List types that implement a `remove` function 


 [0] http://ddili.org/ders/d.en/ranges.html
 [1] https://dlang.org/phobos/std_algorithm_iteration.html#filter
 [2] https://dlang-community.github.io/containers/index.html



quite a memory overhead, operator overloading, etc. Quite tedius, 
imo. Now, if I went to use filter, could I remove that item and 
somewhat get an array back, without perform a new array 
allocation? currently i'm with this, that as far i know, does 
perform memory allocation by array() call:

arr = arr.filter!(x => x != value).array;
Jan 07 2021
parent Mike Parker <aldacron gmail.com> writes:
On Friday, 8 January 2021 at 03:22:49 UTC, Jack wrote:


 tedius, imo. Now, if I went to use filter, could I remove that 
 item and somewhat get an array back, without perform a new 
 array allocation? currently i'm with this, that as far i know, 
 does perform memory allocation by array() call:

 arr = arr.filter!(x => x != value).array;


See std.algorithm.mutation.remove. One overload takes an offset, 
but the other takes a predicate. Example from the docs:

```
static immutable base = [1, 2, 3, 2, 4, 2, 5, 2];

int[] arr = base[].dup;

// using a string-based predicate
writeln(remove!("a == 2")(arr)); // [1, 3, 4, 5]

// The original array contents have been modified,
// so we need to reset it to its original state.
// The length is unmodified however.
arr[] = base[];

// using a lambda predicate
writeln(remove!(a => a == 2)(arr)); // [1, 3, 4, 5]
```
Jan 07 2021
prev sibling parent reply Mike Parker <aldacron gmail.com> writes:
On Friday, 8 January 2021 at 02:53:47 UTC, Jack wrote:

 I coduln't find an equivalent in the documentation, I could see 
 appender, Array, container etc but none of has a Remove(T item) 

 do have to write one myself or I just couldn't find?


SList and DList both have a function called linearRemoveElement.

https://dlang.org/phobos/std_container_slist.html#.SList.linearRemoveElement
https://dlang.org/phobos/std_container_dlist.html#.DList.linearRemoveElement
Jan 07 2021
parent Jack <jckj33 gmail.com> writes:
On Friday, 8 January 2021 at 03:14:34 UTC, Mike Parker wrote:

 On Friday, 8 January 2021 at 02:53:47 UTC, Jack wrote:

 I coduln't find an equivalent in the documentation, I could 
 see appender, Array, container etc but none of has a Remove(T 

 and I do have to write one myself or I just couldn't find?


 SList and DList both have a function called linearRemoveElement.

 https://dlang.org/phobos/std_container_slist.html#.SList.linearRemoveElement
 https://dlang.org/phobos/std_container_dlist.html#.DList.linearRemoveElement


seems to do the job I want, thanks
Jan 07 2021