Re: InsertBefore in DList of structs
On Tuesday, 5 March 2019 at 08:39:56 UTC, drug wrote: On 05.03.2019 2:01, r-const-dev wrote: [...] dataPoints is an aggregate type variable, not a range and slice operator opSlice/[] returns a range of this aggregate type. I have no appropriate links unfortunately but these can be useful https://dlang.org/phobos/std_container_dlist.html#.DList.opSlice - this operator returns a range https://dlang.org/phobos/std_container_dlist.html#.DList.Range - this is range that allows to iterate over DList elements http://ddili.org/ders/d.en/ranges.html - intro to ranges [...] `find` returns a range that starts from the key `until` returns a range of all elements before the key https://run.dlang.io/is/1kpOUx [...] Thank you for clarifications, it makes sense to me now.
Re: InsertBefore in DList of structs
On 05.03.2019 2:01, r-const-dev wrote: Thanks, seems that using dataPoints[] makes dataPoints usable as an range. How can I learn more about [] operator? I'm not sure I understand how is this documented in DList. dataPoints is an aggregate type variable, not a range and slice operator opSlice/[] returns a range of this aggregate type. I have no appropriate links unfortunately but these can be useful https://dlang.org/phobos/std_container_dlist.html#.DList.opSlice - this operator returns a range https://dlang.org/phobos/std_container_dlist.html#.DList.Range - this is range that allows to iterate over DList elements http://ddili.org/ders/d.en/ranges.html - intro to ranges Find does the job! What's the difference between find and until? `find` returns a range that starts from the key `until` returns a range of all elements before the key https://run.dlang.io/is/1kpOUx P.S. `findSplit` returns three ranges, first one contains all elements before the key like `until`, second range contains all elements that are equal to the key and third range contains the rest
Re: InsertBefore in DList of structs
On Monday, 4 March 2019 at 10:09:19 UTC, drug wrote:
On 04.03.2019 13:03, drug wrote:
insertStable needs DList.Range, not Until!... one. You can do
something like this https://run.dlang.io/is/A2vZjW
Oops, it was wrong example, I'd recommend this way -
https://run.dlang.io/is/ugPL8j
```
import std.algorithm, std.container, std.stdio;
struct DataPoint {
immutable ulong time;
ulong value;
}
void main() {
auto dataPoints = DList!DataPoint([
DataPoint(10_000_000, 1),
DataPoint(30_000_000, 3),
DataPoint(40_000_000, 4),
]);
auto time = 30_000_000;
auto r = findSplit!((a, b) => a.time == b)(dataPoints[],
[time]);
auto dp = dataPoints[].find(r[1].front);
writeln("before: ", dataPoints[]);
dataPoints.insertBefore(dp, DataPoint(20_000_000, 2));
writeln("after: ", dataPoints[]);
}
```
Thanks, seems that using dataPoints[] makes dataPoints usable as
an range. How can I learn more about [] operator? I'm not sure I
understand how is this documented in DList.
Find does the job! What's the difference between find and until?
Re: InsertBefore in DList of structs
On 04.03.2019 13:03, drug wrote:
insertStable needs DList.Range, not Until!... one. You can do something
like this https://run.dlang.io/is/A2vZjW
Oops, it was wrong example, I'd recommend this way -
https://run.dlang.io/is/ugPL8j
```
import std.algorithm, std.container, std.stdio;
struct DataPoint {
immutable ulong time;
ulong value;
}
void main() {
auto dataPoints = DList!DataPoint([
DataPoint(10_000_000, 1),
DataPoint(30_000_000, 3),
DataPoint(40_000_000, 4),
]);
auto time = 30_000_000;
auto r = findSplit!((a, b) => a.time == b)(dataPoints[], [time]);
auto dp = dataPoints[].find(r[1].front);
writeln("before: ", dataPoints[]);
dataPoints.insertBefore(dp, DataPoint(20_000_000, 2));
writeln("after: ", dataPoints[]);
}
```
Re: InsertBefore in DList of structs
On 04.03.2019 11:14, r-const-dev wrote:
I have a DList of structs, DataPoint, ordered by a struct field, time.
I'm trying to insert a new entry preserving order, so I'm trying to use
`until` to find the insertion point and `insertBefore` with the result.
struct DataPoint {
immutable ulong time;
ulong value;
}
void main() {
DList!DataPoint dataPoints;
void incrementAt(ulong time) {
auto dataPoint = until!(dp => dp.time >= time)(dataPoints);
if (dataPoint.time == time) {
++dataPoint.value;
} else {
dataPoints.insertBefore(dataPoint, DataPoint(time, 1));
}
}
}
But I'm getting:
/dlang/dmd/linux/bin64/../../src/phobos/std/algorithm/searching.d(4898):
Error: template instance `onlineapp.main.incrementAt.Until!(__lambda2,
DList!(DataPoint), void)` does not match template declaration
Until(alias pred, Range, Sentinel) if (isInputRange!Range)
onlineapp.d(14): Error: template instance
`onlineapp.main.incrementAt.until!((dp) => dp.time >= time,
DList!(DataPoint))` error instantiating
dataPoints itself isn't a range, you need to use dataPoints[]. Also
insertStable needs DList.Range, not Until!... one. You can do something
like this https://run.dlang.io/is/A2vZjW
InsertBefore in DList of structs
I have a DList of structs, DataPoint, ordered by a struct field,
time. I'm trying to insert a new entry preserving order, so I'm
trying to use `until` to find the insertion point and
`insertBefore` with the result.
struct DataPoint {
immutable ulong time;
ulong value;
}
void main() {
DList!DataPoint dataPoints;
void incrementAt(ulong time) {
auto dataPoint = until!(dp => dp.time >=
time)(dataPoints);
if (dataPoint.time == time) {
++dataPoint.value;
} else {
dataPoints.insertBefore(dataPoint, DataPoint(time,
1));
}
}
}
But I'm getting:
/dlang/dmd/linux/bin64/../../src/phobos/std/algorithm/searching.d(4898): Error:
template instance `onlineapp.main.incrementAt.Until!(__lambda2,
DList!(DataPoint), void)` does not match template declaration Until(alias pred,
Range, Sentinel) if (isInputRange!Range)
onlineapp.d(14): Error: template instance
`onlineapp.main.incrementAt.until!((dp) => dp.time >= time,
DList!(DataPoint))` error instantiating
