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--- python [2021/08/02 17:57] – [Cheat sheet] utedass
+++ python [2022/12/05 16:26] (current) – utedass
@@ Line 4: / Line 4: @@
   * pyserial -- Comport
   * matplotlib -- Matlabliknande plotverktyg
-  * numpy -- Matlabliknande matte
+  * [[python:numpy]] -- Matlabliknande matte
   * pandas -- Importera och exportera till olika filformat, ex CSV, tydligen också för att behandla data
@@ Line 18: / Line 18: @@
   * Hur man läser syntaxguide i pythons dokumentation
   * Hur man använder context managers
+  * Vad är generators, hur fungerar yield
+  * Vem fan kom på syntaxen ''mylist = [x*x for x in range(3)]'' och när kan den användas?
+  * ^ Verkar vara [[https://www.w3schools.com/python/python_lists_comprehension.asp|List comprehensions]]
 ====== Cheat sheet ======
@@ Line 28: / Line 30: @@
 populated_tuple = (1, 2, "Kalle", 4.32)
 singleton_tuple = (3,)
+print(populated_tuple[2]) # Prints Kalle
 # Ranges are also immutable
@@ Line 55: / Line 58: @@
 all_keys = list(my_dict)
 leet = my_dict['shit']
+# Dictionaries can be unpacked and used as arguments to a function
+dude = {a: 4, b: 5}
+function_that_takes_a_and_b(**dude)
 # Set types must contain hashable objects. They are not ordered and cannot be indexed
@@ Line 82: / Line 89: @@
 <code python>
+# Name mangling for double underscore and less than one trailing underscores
+class Foo(object):
+    yo = None     # => foo_object.yo
+    _yo = None    # => foo_object._yo
+    __yo = None   # => foo_object._Foo__yo
+    __yo__ = None # => foo_object.__yo__
 # To copy an object
 import copy
@@ Line 88: / Line 104: @@
-====== Parser ======
+====== Argument parser ======
 <code python>
@@ Line 133: / Line 149: @@
 ====== Exceptions ======
 [[https://docs.python.org/3/tutorial/errors.html]]
+[[https://docs.python.org/3/library/exceptions.html|Predefined exceptions]]
 <code python>
@@ Line 156: / Line 174: @@
 raise ValueError("Passed array is not of the right shape")
 </code>
+====== Decorators ======
+Syntactic sugar based on functions that return function objects.
+[[https://www.programiz.com/python-programming/decorator|Good guide]], much of the info here is stolen from this site.
+===== Basics =====
+<code python>
+# Given this function, which is called a decorator function
+def my_decorator(func):
+    def wrapper():
+        print("I got decorated!")
+        func()
+    return wrapper
+# Then one could write something like this
+def boring():
+    print("Normal function")
+pimped_boring = my_decorator(boring)
+pimped_boring()
+# Or one could overwrite the boring function name
+def boring():
+    print("Normal function")
+boring = my_decorator(boring)
+# which is equivalent to write this short-cut syntax
+@my_decorator
+def boring():
+    print("Normal function")
+</code>
+===== Chaining =====
+<code python>
+# Given the two decorators
+def star(func):
+    def inner(*args, **kwargs):
+        print("*" * 30)
+        func(*args, **kwargs)
+        print("*" * 30)
+    return inner
+def percent(func):
+    def inner(*args, **kwargs):
+        print("%" * 30)
+        func(*args, **kwargs)
+        print("%" * 30)
+    return inner
+# Then
+@star
+@percent
+def printer(msg):
+    print(msg)
+# is equivalent to
+def printer(msg):
+    print(msg)
+printer = star(percent(printer))
+</code>
+===== Property decorator and setter decorators =====
+[[https://stackoverflow.com/questions/17330160/how-does-the-property-decorator-work-in-python|Explained at stackoverflow]]
+<code python>
+class MyClass(object):
+    def __init__(self):
+        self._my_property_value = None # Placeholder variable, so getter function works
+        self.my_property = 123 # Will call the proper setter function
+    @property
+    def my_property(self):
+        return self._my_property_value
+    @my_property.setter
+    def my_property(self, value):
+        if value < 0:
+            self._my_property_value = -value * 10
+        else:
+            self._my_property_value = value/10
+my_instance = MyClass()
+my_instance.my_property = -30
+print(my_instance.my_property) # Prints 300
+</code>
+====== tkinter ======
+[[https://tkdocs.com/tutorial/menus.html|Good site]]
+[[https://tcl.tk/man/tcl8.6/TkCmd/contents.htm|tk reference]]
+[[https://web.archive.org/web/20200201190621/http://effbot.org/tkinterbook/text.htm|Archived tutorial from effbot.org]]