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what is the difference between 'transform' and 'fit_transform' in sklearn

...is meant for when you have already computed PCA, i.e. if you have already called its .fit method. In [12]: pc2 = RandomizedPCA(n_components=3) In [13]: pc2.transform(X) # can't transform because it does not know how to do it. -------------------------------------------------------------------------...
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Cross-Origin Request Headers(CORS) with PHP headers

... Access-Control-Allow-Headers does not allow * as accepted value, see the Mozilla Documentation here. Instead of the asterisk, you should send the accepted headers (first X-Requested-With as the error says). ...
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What's the (hidden) cost of Scala's lazy val?

...nswered Jun 15 '10 at 7:51 oxbow_lakesoxbow_lakes 127k5252 gold badges305305 silver badges442442 bronze badges ...
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What are the advantages of NumPy over regular Python lists?

... Python objects, at least 4 bytes per pointer plus 16 bytes for even the smallest Python object (4 for type pointer, 4 for reference count, 4 for value -- and the memory allocators rounds up to 16). A NumPy array is an array of uniform values -- single-precision numbers takes 4 bytes each, double-pr...
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StringIO in Python3

... of the question and is included only as something to consider when generically addressing the missing StringIO module. For a more direct solution the message TypeError: Can't convert 'bytes' object to str implicitly, see this answer. ...
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Databinding an enum property to a ComboBox in WPF

... the amount of code required by WPF to accomplish simpliest of things is really headspinning – Konrad Morawski Aug 29 '12 at 14:36 1 ...
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Difference between fold and reduce?

... So basically instead of doing fold, you can simply add that initial value to the start of the list and do reduce? What's the point of fold then? – Pacerier Feb 7 '17 at 9:42 ...
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How to calculate the bounding box for a given lat/lng location?

... I suggest to approximate locally the Earth surface as a sphere with radius given by the WGS84 ellipsoid at the given latitude. I suspect that the exact computation of latMin and latMax would require elliptic functions and would not yield an appreciable ...
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Pointers in Python?

...ur request is utterly impossible. Why ask for something impossible and totally different from the (possible) thing you actually want?! Maybe you don't realize how drastically different barenames and decorated names are. When you refer to a barename a, you're getting exactly the object a was last ...
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Compare object instances for equality by their attributes

...s: >>> x == y True Note that implementing __eq__ will automatically make instances of your class unhashable, which means they can't be stored in sets and dicts. If you're not modelling an immutable type (i.e. if the attributes foo and bar may change value within the lifetime of your obje...