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--- other:python:misc_by_jyp [2022/05/23 18:01] – [numpy related stuff] Changed the VIEW update warnng example jypeter
+++ other:python:misc_by_jyp [2022/12/12 13:13] – [Storing objects and data in a file (shelve and friends)] jypeter
@@ Line 228: / Line 228: @@
 </code>
+==== Storing objects and data in a file (shelve and friends) ====
+The built-in [[other:python:jyp_steps#the_shelve_package|shelve]] module can be **easily** used for storing temporary/intermediate data
+More options:
+  * Some [[other:python:jyp_steps#data_file_formats|non-NetCDF]] file formats
+  * Working with [[other:python:jyp_steps#netcdf_filesusing_cdms2_xarray_and_netcdf4|NetCDF]] files
 ==== Sorting ====
@@ Line 248: / Line 256: @@
 ==== numpy related stuff ====
+=== Using a numpy array to store arbitrary objects ===
+The numpy arrays are usually used to store [[https://numpy.org/doc/stable/reference/arrays.scalars.html|scalars]] of the same type (see also the [[https://numpy.org/doc/stable/reference/arrays.dtypes.html|Data type objects (dtype)]]), very often numerical values.
+It is also possible to store **arbitrary** Python objects in an array, rather than using nested lists or dictionaries!
+<code>>>> some_array = np.empty((2, 3), dtype=object)
+>>> some_array
+array([[None, None, None],
+       [None, None, None]], dtype=object)
+>>> some_array.shape
+(2, 3)
+>>> print(some_array[-1, -1])
+None
+>>> some_array[-1, 0] = filled_contour # e.g. save an existing cartopy filled contour object
+>>> some_array
+array([[None, None, None],
+       [<cartopy.mpl.contour.GeoContourSet object at 0x2ab679e8bf10>,
+        None, None]], dtype=object)</code>
 === Dealing with a variable number of indices ===