Grouping & Selection¶
Use group() and select() to combine multiple elements or pick specific pads
before connecting.
Grouping Elements¶
group() combines multiple elements so connect() sees all their pads as one
unit:
from sgn import Pipeline, IterSource, NullSink
from sgn.groups import group
src1 = IterSource(name="s1", source_pad_names=["H1"], iters={"H1": [1, 2]})
src2 = IterSource(name="s2", source_pad_names=["L1"], iters={"L1": [3, 4]})
snk1 = NullSink(name="k1", sink_pad_names=["H1"])
snk2 = NullSink(name="k2", sink_pad_names=["L1"])
p = Pipeline()
p.connect(group(src1, src2), group(snk1, snk2)) # H1->H1, L1->L1
p.run()
Selecting Pads¶
select() narrows an element to specific pads, ignoring the rest:
from sgn import Pipeline, IterSource, NullSink
from sgn.groups import select
src = IterSource(
name="src",
source_pad_names=["H1", "L1", "V1"],
iters={"H1": [1], "L1": [2], "V1": [3]},
)
snk = NullSink(name="snk", sink_pad_names=["H1", "L1"])
p = Pipeline()
p.connect(select(src, "H1", "L1"), snk) # V1 is excluded
Combining Group and Select¶
Mix group() and select() for complex topologies:
from sgn import Pipeline, IterSource, NullSink
from sgn.groups import group, select
dedicated = IterSource(name="ded", source_pad_names=["H1"], iters={"H1": [1]})
multi = IterSource(
name="multi",
source_pad_names=["L1", "V1"],
iters={"L1": [2], "V1": [3]},
)
snk_h1 = NullSink(name="sh", sink_pad_names=["H1"])
snk_l1 = NullSink(name="sl", sink_pad_names=["L1"])
sources = group(dedicated, select(multi, "L1")) # H1 + L1 only
sinks = group(snk_h1, snk_l1)
p = Pipeline()
p.connect(sources, sinks)
p.run()
Explicit Linking with Groups¶
When automatic matching doesn't work, add a link_map:
from sgn import Pipeline, IterSource, NullSink
from sgn.groups import group
src1 = IterSource(name="s1", source_pad_names=["out_a"], iters={"out_a": [1]})
src2 = IterSource(name="s2", source_pad_names=["out_b"], iters={"out_b": [2]})
snk1 = NullSink(name="k1", sink_pad_names=["in_x"])
snk2 = NullSink(name="k2", sink_pad_names=["in_y"])
p = Pipeline()
p.connect(
group(src1, src2),
group(snk1, snk2),
link_map={"in_x": "out_a", "in_y": "out_b"},
)
p.run()
Iterating Over Pads¶
Use select_by_source() or select_by_sink() to iterate over individual pads
in a group or selection, yielding one PadSelection per pad: