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--- notes:python_cheat_sheet [2026/07/29 13:41]
103.86.199.234 old revision restored (2026/06/10 03:40)
+++ notes:python_cheat_sheet [2026/08/01 12:05] (current)
114.119.158.118 old revision restored (2026/05/19 02:35)
@@ Line 1: / Line 1: @@
 ====== Python Cheat Sheet ======
-===== Overview =====
 [[http://www.python.org/ | Python]] is a dynamic object-oriented programming language with extensive standard libraries. These notes summarize the [[http://docs.python.org/3.1/tutorial/ | Python 3.1 tutorial]].
@@ Line 43: / Line 41: @@
   * Other sequence types include tuples ( (1,2) or 1,2) and sets ({1,2} or set(1,2)).
-===== Strings =====
+===== Input/Output =====
   * Strings can be enclosed with double or single-quotes.
   * \ in a string by itself goes to the next line but does not insert a newline (\n does).
@@ Line 51: / Line 49: @@
   * But strings can't be modified using slices or indexes.
   * [[http://docs.python.org/3.1/library/stdtypes.html#string-methods | String methods]] include strip, format, capitalize etc.
+  * //formatstring.format(tuple)// is the [[http://docs.python.org/3.1/library/string.html#formatspec | new-style printf]] equivalent. The [[http://docs.python.org/3.1/library/stdtypes.html#old-string-formatting | old-style]] was //formatstring % (tuple)// which uses C-type format strings.
+  * str() returns a readable representation, repr() returns a canonical representation of any object.
+  * To open a file <code python> open('/tmp/workfile', 'w') </code>
+  * [[http://docs.python.org/3.1/library/stdtypes.html#file-objects | File methods]] include read, readline, write.
+  * //pickle// contains [[http://docs.python.org/3.1/library/pickle.html | load and dump methods]] for serializing objects. Support should be added for new object types.
 ===== Control Flow =====
@@ Line 94: / Line 99: @@
   * Packages can be used to group modules. Packages should be in a named directory with an __init__.py file optionally containing initialization code. E.g. import sound.effects.echo .
   * . is the current package, .. is the parent package etc.
-===== Input/Output =====
-  * str() returns a readable representations, repr() returns a canonical representation
-  * Strings have several formatting methods.
-  * //formatstring.format(tuple)// is the [[http://docs.python.org/3.1/library/string.html#formatspec | new-style printf]] equivalent. The [[http://docs.python.org/3.1/library/stdtypes.html#old-string-formatting | old-style]] was //formatstring % (tuple)// which uses C-type format strings.
-  * To open a file <code python> open('/tmp/workfile', 'w') </code>
-  * [[http://docs.python.org/3.1/library/stdtypes.html#file-objects | File methods]] include read, readline, write.
-  * //pickle// contains [[http://docs.python.org/3.1/library/pickle.html | load and dump methods]] for serializing objects. Support should be added for new object types.
 ===== Error Handling =====
@@ Line 108: / Line 104: @@
   * Syntax errors are parsing errors, exceptions are runtime errors.
   * Exceptions are class objects in the exceptions module. [[http://docs.python.org/3.1/library/exceptions.html#bltin-exceptions | List of builtin exceptions]].
-  * Exception handling is supported using try..except..else..finally :
+  * Exception handling is supported using try..except..else..finally :<code python>
-<code python>
 try:
-   result = x / y
+    result = x / y
 except ZeroDivisionError:
-   print("division by zero!")
+    print("division by zero!")
 except Exception as inst:
-   print(type(inst))    # the exception instance
+    print(type(inst))    # the exception instance
-   print(inst.args)     # arguments stored in .args
+    print(inst.args)     # arguments stored in .args
-   print(inst)          # also prints .args
+    print(inst)          # also prints .args
 else:
-   print("result is", result)
+    print("result is", result)
 finally:
-   print("executing finally clause")
+    print("executing finally clause")
 </code>
   * Errors can be raised using ''raise Exception('mine')'' or just ''raise'' in an exception handler.
   * New exception classes can be created and should derive from the Exception class.
-  * ''with'' can be used to automatically call the cleanup actions of an object e.g.
+  * ''with'' can be used to automatically call the cleanup actions of an object e.g. <code python>
-<code python>
 with open("myfile.txt") as f:
     for line in f:

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