Simplfy field fetch in plink

Author: benjeffery

bio2zarr/plink.py

@@ -33,10 +33,8 @@ def iter_alleles(self, start, stop, num_alleles):
             yield alleles
 
     def iter_field(self, field_name, shape, start, stop):
-        data = {
-            "position": self.bed.bp_position,
-        }[field_name]
-        yield from data[start:stop]
+        assert field_name == "position" # Only position field is supported from plink
+        yield from self.bed.bp_position[start:stop]
 
     def iter_genotypes(self, shape, start, stop):
         bed_chunk = self.bed.read(slice(start, stop), dtype=np.int8).T