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Diffstat (limited to 'Doc/reference/compound_stmts.rst')
| -rw-r--r-- | Doc/reference/compound_stmts.rst | 45 |
1 files changed, 31 insertions, 14 deletions
diff --git a/Doc/reference/compound_stmts.rst b/Doc/reference/compound_stmts.rst index 927930a..ffd7423 100644 --- a/Doc/reference/compound_stmts.rst +++ b/Doc/reference/compound_stmts.rst @@ -78,7 +78,10 @@ on a separate line for clarity. The :keyword:`if` statement =========================== -.. index:: statement: if +.. index:: + statement: if + keyword: elif + keyword: else keyword: elif keyword: else @@ -105,6 +108,7 @@ The :keyword:`while` statement statement: while keyword: else pair: loop; statement + keyword: else The :keyword:`while` statement is used for repeated execution as long as an expression is true: @@ -139,6 +143,9 @@ The :keyword:`for` statement keyword: else pair: target; list pair: loop; statement + keyword: in + keyword: else + pair: target; list object: sequence The :keyword:`for` statement is used to iterate over the elements of a sequence @@ -208,7 +215,10 @@ returns the list ``[0, 1, 2]``. The :keyword:`try` statement ============================ -.. index:: statement: try +.. index:: + statement: try + keyword: except + keyword: finally .. index:: keyword: except The :keyword:`try` statement specifies exception handlers and/or cleanup code @@ -223,7 +233,8 @@ for a group of statements: try2_stmt: "try" ":" `suite` : "finally" ":" `suite` -The :keyword:`except` clause(s) specify one or more exception handlers. When no + +The :keyword:`except` clause(s) specify one or more exception handlers. When no exception occurs in the :keyword:`try` clause, no exception handler is executed. When an exception occurs in the :keyword:`try` suite, a search for an exception handler is started. This search inspects the except clauses in turn until one @@ -379,6 +390,10 @@ The execution of the :keyword:`with` statement proceeds as follows: location for the kind of exit that was taken. + In Python 2.5, the :keyword:`with` statement is only allowed when the + ``with_statement`` feature has been enabled. It is always enabled in + Python 2.6. + .. seealso:: :pep:`0343` - The "with" statement @@ -393,8 +408,10 @@ Function definitions ==================== .. index:: - pair: function; definition statement: def + pair: function; definition + pair: function; name + pair: name; binding object: user-defined function object: function pair: function; name @@ -513,13 +530,13 @@ Class definitions ================= .. index:: - pair: class; definition - statement: class object: class - single: inheritance + statement: class + pair: class; definition pair: class; name pair: name; binding pair: execution; frame + single: inheritance A class definition defines a class object (see section :ref:`types`): @@ -554,13 +571,13 @@ is equivalent to :: Foo = f1(arg)(f2(Foo)) **Programmer's note:** Variables defined in the class definition are class -variables; they are shared by all instances. To define instance variables, they -must be given a value in the :meth:`__init__` method or in another method. Both -class and instance variables are accessible through the notation -"``self.name``", and an instance variable hides a class variable with the same -name when accessed in this way. Class variables with immutable values can be -used as defaults for instance variables. Descriptors can be used to create -instance variables with different implementation details. +can be set in a method with ``self.name = value``. Both class and instance +variables are accessible through the notation "``self.name``", and an instance +variable hides a class variable with the same name when accessed in this way. +Class variables can be used as defaults for instance variables, but using +mutable values there can lead to unexpected results. For :term:`new-style +class`\es, descriptors can be used to create instance variables with different +implementation details. .. XXX add link to descriptor docs above |