Re: [matplotlib-devel] custom symbol patch

[John H. <jdh...@ac...>]

>>>>> "Manuel" == Manuel Metz <mm...@as...> writes:

    Manuel> There is a subtle but essential difference ;-) : for i in
    Manuel> xrange(1,len(r), 2 ) ^^^ , i.e. every second value gets
    Manuel> rescaled. But there is probably a more "pythonic" way to
    Manuel> do that:

    Manuel> 	r = 1.0/math.sqrt(math.pi) # unit area r = asarray(
    Manuel> [r,0.5*r]*self.numsides )

    Manuel> I'm not aware of a better way to do this with numerix :-(

Oops, sorry I missed that.  I think what you want is then

        scale = 0.5/math.sqrt(math.pi)  
        r = scale*ones(self.numsides*2)
        r[1::2] *= 0.5

    Manuel> The patch against the latest svn revision (2810) is
    Manuel> attached.

OK, if I could make a few more suggestions (I feel like a customer at
a restaurant where every time the waiter brings me a cup of coffee I
ask "just one more thing"...)

+        old_ymin,old_ymax = self.get_ylim()

The matplotlib style guidelines are
  
  UpperCase : classes
  lower_underscore  : functions and methods
  lower or lowerUpper : variables or attributes

For shortish variable names, I prefer

        oldymin, oldymax = self.get_ylim()

+        if isinstance(marker, str) or isinstance(marker, unicode):
+            # the standard way to define symbols using a string character
+            sym = syms.get(marker)

+        if isinstance(marker, tuple) or isinstance(marker, list):
+            # accept marker to be:
+            #    (numsides, style, [angle])

+            if isinstance(marker[0], int) or isinstance(marker[0], long):
+                # (numsides, style, [angle])

Here you should use "duck typing" not "type checking" (google "duck
typing").  matplotlib.cbook provides several duck typing functions, eg
is_stringlike, iterable and is_numlike.  Take a look at is_numlike

def is_numlike(obj):
    try: obj+1
    except TypeError: return False
    else: return True

Ie, if it acts like a number (you can add one to it) then we'll treat
it as a number.  This allows users to provide other integer like
classes which are not ints or longs.  Everytime you use isinstance,
take a 2nd look.  There may be a better way.

I'll await your updated patch :-)

JDH