PEP 308: Obfuscated Nested Ternaries (Not)

Terry Reedy tjreedy at udel.edu
Thu Feb 20 16:59:49 CET 2003


"Gerrit Holl" <gerrit at nl.linux.org> wrote in message
news:mailman.1045749596.2787.python-list at python.org...
> For the Obfuscated Contest: rewrite this peace of code
> using ternaries. Preferably with a lot of ('s and )'s :

Instead, I will rewrite so more clear than original.

seq = (
    x > 0 ?
        y > 0 ? (tl, br, b, br, r, br) :
        y==0 ? (l, r, t, r, b, r) :
                    (bl, tr, t, tr, r, tr) :
    x==0 ?
        y > 0 ? (t, b, l, b, r, b) :
        y==0 ? (tl, tr, br, bl, tl) :
                    (b, t, l, t, r, t) :
    # x < 0
        y > 0 ? (tr, bl, b, bl, l, bl) :
        y==0 ? (r, l, t, l, b, l) :
                    (br, tl, t, tl, l, tl)
        )

To me, this is clearer than the if:elif:else statement since it makes
it  immediately obvious that seq and only seq is being assigned a
value.  In your original form, one has to check that all targets are
the same.  If the target were qxyz_ade[i3][j4], this would be even
more difficult.  Assignment to one variable should be one statement.

Thanks for the choice to should what a ternary can do when properly
used and properly formatted.  (I now favor the ?: form used by other
languages.)

Terry J. Reedy



Terry J. Reedy






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