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<P><FONT size=2>Sorry this is in HTML, but the documentation below requires
it.</FONT></P>
<P><FONT size=2>The latest source release is 17.2.0.<BR><BR>Revised
documentation in HTML and PDF is available at <A target=_blank
href="http://numpy.sourceforge.net">http://numpy.sourceforge.net</A>.<BR><BR>Package
MA contains a number of new constructors. The complete list is:</P>
<H6 class=FM2Heading><A name=pgfId-298181></A><A name=73354></A>Constructing
masked arrays</H6>
<OL>
<LI class=Numbered1><A name=pgfId-305574></A><A name=marker-305800></A>array
(data, typecode = None, copy = 1, savespace = 0, mask = None, fill_value =
None) creates a masked array with the given data and mask. The name array is
simply an alias for the class name, MA. This constructor sets the data area of
the resulting masked array to filled (data, value = fill_value, copy = copy,
savespace = savespace), the mask to make_mask (mask, savespace), and the fill
value is set to fill_value. The class name MA may also be used instead of the
name array.
<LI class=Numbered><A name=pgfId-305587></A><A
name=marker-305801></A>masked_array (data, mask = None, fill_value = None) is
an easier to use version of array, for the common case of typecode = None,
copy = 0. When data is newly-created this function can be used to make it a
masked array without copying the data if data is already a Numeric array.
<LI class=Numbered><A name=pgfId-303765></A><A
name=marker-304072></A>masked_values (data, value, rtol=1.e-5, atol=1.e-8,
typecode = None, copy = 1, savespace = 0) constructs a masked array whose mask
is set at those places where <BR>abs (data - value) < atol + rtol * abs
(data). <BR>That is a careful way of saying that those elements of the data
that have value = value (to within a tolerance) are to be treated as invalid.
<LI class=Numbered><A name=pgfId-305796></A><A
name=marker-305802></A>masked_object (data, value, copy=1, savespace=0)
creates a masked array with those entries marked invalid that are equal to
value. Again, copy and savespace are passed on to the Numeric array
constructor.
<LI class=Numbered><A name=pgfId-307728></A><A
name=marker-307732></A>masked_where (condition, data) creates a masked array
whose shape is that of condition, whose values are those of data, and which is
masked where elements of condition are true.
<LI class=Numbered><A name=pgfId-307764></A><A
name=marker-307789></A>masked_greater (data, value) is equivalent to
masked_where (greater(data, value), data)). Similarly, <A
name=marker-307793></A>masked_greater_equal, <A
name=marker-307797></A>masked_equal, <A
name=marker-307801></A>masked_not_equal, <A
name=marker-307805></A>masked_less, <A
name=marker-307809></A>masked_less_equal are called in the same way with the
obvious meanings. Note that for floating point data, <A
name=marker-307810></A>masked_values is preferable to masked_equal in most
cases. </LI></OL>
<P class=Body><A name=pgfId-305283></A>On entry to any of these constructors,
data must be any object which the Numeric package can accept to create an array
(with the desired typecode, if specified). The mask if given must be None or any
object that can be turned into a Numeric array of integer type (it will be
converted to typecode MaskType, if necessary), have the same shape as data, and
contain only values of 0 or 1.</P>
<P class=Body><A name=pgfId-306531></A>If the mask is not None but its shape
does not match that of data, an exception will be thrown, unless one of the two
is of length 1, in which case the scalar will be resized (using Numeric.resize)
to match the other.</P>
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