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--- other:python:misc_by_jyp [2022/12/12 15:24] – Added the global variables section jypeter
+++ other:python:misc_by_jyp [2023/04/27 11:47] – [Data representation] Improved jypeter
@@ Line 32: / Line 32: @@
 <code>sys.exit('Some optional message about why we are stopping')</code>
+===== Data representation =====
+A few notes for a future section or page about about data representation (bits and bytes) on disk and in memory, vs data format
+  * Binary data representation of some numbers:
+    * [[https://en.wikipedia.org/wiki/Integer_(computer_science)|Integers]]
+      * Range:
+        * 4-byte integers (''numpy.int32''): −2,147,483,648 to 2,147,483,647
+        * 8-byte integers (''numpy.int64''): −9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
+      * Note: using [[https://en.wikipedia.org/wiki/Two%27s_complement|two's complement]] for negative integers
+    * [[https://en.wikipedia.org/wiki/IEEE_754|Floating point numbers]] (//IEEE 754// standard aka //IEEE Standard for Binary Floating-Point for Arithmetic//)
+      * Range:
+        * 4-byte float (''numpy.float32''): ~8 significant digits * 10E±38
+          * See also [[https://en.wikipedia.org/wiki/Single-precision_floating-point_format|Single-precision floating-point format|Single-precision floating-point format]]
+        * 8-byte float (''numpy.float64''): ~15 significant digits * 10E±308
+      * Special values:
+        * [[https://en.wikipedia.org/wiki/NaN|NaN]] (''numpy.nan''): //Not a Number//
+        * Infinity (''-numpy.inf'' and ''numpy.inf'')
+    * [[https://en.wikipedia.org/wiki/Bit_numbering|Bit numbering]]
+    * [[https://en.wikipedia.org/wiki/Endianness|Endianness]]
+  * Array addressing
+  * disk and ram usage: how to check the usage (available ram and disk), best practice on multi-user systems (how much allowed?)
+    * ''du'', ''df'', ''cat /proc/meminfo'', ''top''
+  * understanding and reverse-engineering //binary// format
+    * ''od'', ''strings''
+  * binary vs text format: ascii, utf, raw
+    * text related functions in python: ''str'', ''int'', ''float'', ''ord'', ...
+      * lists conversion with ''map'' and ''join''
+  * Misc : ''md5sum''
 ===== Checking if a file/directory is writable by the current user =====
@@ Line 453: / Line 486: @@
 >>> np.add.reduceat(np.sort(vals), slices_indices)
 array([3. , 4.5, 8. ])</code>
+===== matplotlib related stuff =====
+==== Working with time axes (and ticks) ====
+If you have problems setting the limits of a time axis, choosing the ticks' locations, or specifying the style of the labels, you should check the:
+  * [[https://matplotlib.org/stable/gallery/index.html#ticks|Ticks examples' gallery]]
+  * [[https://matplotlib.org/stable/gallery/text_labels_and_annotations/date.html|Date tick labels example]]