get rid of six.iterkeys

[fchapoton]

only 3 files are touched

CC: @tscrim @jm58660

Component: python3

Author: Frédéric Chapoton

Branch/Commit: 8d9ecb1

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/29077

[fchapoton]

New commits:

238b198

get rid of all calls to six.iterkeys

[fchapoton]

Commit: 238b198

[fchapoton]

Branch: u/chapoton/29077

[fchapoton]

comment:2

green bot, please review

[tscrim]

comment:4

This is kind of a while-we-are-at-it thing, but I think we can avoid the double call to f.dict() and g.dict() here:

         if not coeff:
             coeff = self.base_ring().one()
         else:
-            coeff = self.base_ring()(next(itervalues(f.dict())) /  next(itervalues(g.dict())))
+            nf = next(iter(f.dict().values()))
+            ng = next(iter(g.dict().values()))                    # (trailing whitespace too)
+            coeff = self.base_ring()(nf / ng)
 
-        f = next(iterkeys(f.dict()))
-        g = next(iterkeys(g.dict()))
+        f = next(iter(f.dict()))
+        g = next(iter(g.dict()))

by instead doing

        fd = f.dict()
        gd = g.dict()
        fk = next(iter(fd))
        gk = next(iter(gd))

        if not coeff:
            coeff = self.base_ring().one()
        else:
            coeff = self.base_ring()(fd[fk] / gd[gk])

        f = fk
        g = gk

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

8d9ecb1

trac 29077 suggested improvement

[sagetrac-git]

Changed commit from 238b198 to 8d9ecb1

[fchapoton]

comment:6

Thanks for the review. Here is a proposal, more or less what you suggested.

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:7

That is probably a better idea. Thanks.

[vbraun]

Changed branch from u/chapoton/29077 to 8d9ecb1