std.range.Lockstep/lockstep - multiple declarations
Function lockstep
Iterate multiple ranges in lockstep using a foreach loop. In contrast to
zip it allows reference access to its elements. If only a single
range is passed in, the Lockstep aliases itself away. If the
ranges are of different lengths and s == StoppingPolicy
stop after the shortest range is empty. If the ranges are of different
lengths and s == StoppingPolicy, throw an
exception. s may not be StoppingPolicy, and passing this
will throw an exception.
Lockstep!Ranges lockstep(Ranges...)
(
Ranges ranges
)
if (allSatisfy!(isInputRange, Ranges));
Lockstep!Ranges lockstep(Ranges...)
(
Ranges ranges,
StoppingPolicy s
)
if (allSatisfy!(isInputRange, Ranges));
Iterating over Lockstep in reverse and with an index is only possible
when s == StoppingPolicy, in order to preserve
indexes. If an attempt is made at iterating in reverse when s ==
StoppingPolicy, an exception will be thrown.
By default StoppingPolicy is set to StoppingPolicy.
Limitations
The pure, @safe, @nogc, or nothrow attributes cannot be
inferred for lockstep iteration. zip can infer the first two due to
a different implementation.
See Also
lockstep is similar to zip, but zip bundles its
elements and returns a range.
lockstep also supports reference access.
Use zip if you want to pass the result to a range function.
Example
auto arr1 = [1,2,3,4,5,100];
auto arr2 = [6,7,8,9,10];
foreach (ref a, b; lockstep(arr1, arr2))
{
a += b;
}
writeln(arr1); // [7, 9, 11, 13, 15, 100]
/// Lockstep also supports iterating with an index variable:
foreach (index, a, b; lockstep(arr1, arr2))
{
writeln(arr1[index]); // a
writeln(arr2[index]); // b
}
Struct Lockstep
Iterate multiple ranges in lockstep using a foreach loop. In contrast to
zip it allows reference access to its elements. If only a single
range is passed in, the Lockstep aliases itself away. If the
ranges are of different lengths and s == StoppingPolicy
stop after the shortest range is empty. If the ranges are of different
lengths and s == StoppingPolicy, throw an
exception. s may not be StoppingPolicy, and passing this
will throw an exception.
struct Lockstep(Ranges...)
if (Ranges
Iterating over Lockstep in reverse and with an index is only possible
when s == StoppingPolicy, in order to preserve
indexes. If an attempt is made at iterating in reverse when s ==
StoppingPolicy, an exception will be thrown.
By default StoppingPolicy is set to StoppingPolicy.
Constructors
| Name | Description |
|---|---|
this
(ranges, sp)
|
Limitations
The pure, @safe, @nogc, or nothrow attributes cannot be
inferred for lockstep iteration. zip can infer the first two due to
a different implementation.
See Also
lockstep is similar to zip, but zip bundles its
elements and returns a range.
lockstep also supports reference access.
Use zip if you want to pass the result to a range function.
Example
auto arr1 = [1,2,3,4,5,100];
auto arr2 = [6,7,8,9,10];
foreach (ref a, b; lockstep(arr1, arr2))
{
a += b;
}
writeln(arr1); // [7, 9, 11, 13, 15, 100]
/// Lockstep also supports iterating with an index variable:
foreach (index, a, b; lockstep(arr1, arr2))
{
writeln(arr1[index]); // a
writeln(arr2[index]); // b
}
Authors
Andrei Alexandrescu, David Simcha, Jonathan M Davis, and Jack Stouffer. Credit for some of the ideas in building this module goes to Leonardo Maffi.