diff options
Diffstat (limited to 'Doc/tut')
| -rw-r--r-- | Doc/tut/glossary.tex | 33 | ||||
| -rw-r--r-- | Doc/tut/tut.tex | 37 |
2 files changed, 36 insertions, 34 deletions
diff --git a/Doc/tut/glossary.tex b/Doc/tut/glossary.tex index 538c5ea..b0ac97f 100644 --- a/Doc/tut/glossary.tex +++ b/Doc/tut/glossary.tex @@ -40,7 +40,7 @@ Any class which does not inherit from \class{object}. See The implicit conversion of an instance of one type to another during an operation which involves two arguments of the same type. For example, -{}\code{int(3.15)} converts the floating point number to the integer, +{}\code{int(3.15)} converts the floating point number to the integer {}\code{3}, but in {}\code{3+4.5}, each argument is of a different type (one int, one float), and both must be converted to the same type before they can be added or it will raise a {}\code{TypeError}. Coercion between two @@ -169,7 +169,7 @@ sophisticated, multi-platform GUI application. An object with fixed value. Immutable objects are numbers, strings or tuples (and more). Such an object cannot be altered. A new object has to be created if a different value has to be stored. They play an -important role in places where a constant hash value is needed. For +important role in places where a constant hash value is needed, for example as a key in a dictionary. \index{integer division} @@ -189,7 +189,7 @@ operator. See also \emph{__future__}. \index{interactive} \item[interactive] Python has an interactive interpreter which means that you can try out -things and directly see its result. Just launch \code{python} with no +things and immediately see their results. Just launch \code{python} with no arguments (possibly by selecting it from your computer's main menu). It is a very powerful way to test out new ideas or inspect modules and packages (remember \code{help(x)}). @@ -235,7 +235,7 @@ code that attempts multiple iteration passes. A container object (such as a \class{list}) produces a fresh new iterator each time you pass it to the \function{iter()} function or use it in a {}\keyword{for} loop. Attempting this with an iterator will just -return the same exhausted iterator object from the second iteration +return the same exhausted iterator object used in the previous iteration pass, making it appear like an empty container. \index{list comprehension} @@ -245,7 +245,15 @@ return a list with the results. \code{result = ["0x\%02x" \% x for x in range(256) if x \% 2 == 0]} generates a list of strings containing hex numbers (0x..) that are even and in the range from 0 to 255. The \keyword{if} clause is optional. If omitted, all elements in -{}\code{range(256)} are processed in that case. +{}\code{range(256)} are processed. + + +\index{LBYL} +\item[LBYL] +Look before you leap. This coding style explicitly tests for +pre-conditions before making calls or lookups. This style contrasts +with the \emph{EAFP} approach and is characterized by the presence of +many \keyword{if} statements. \index{mapping} \item[mapping] @@ -265,13 +273,6 @@ have been used for logging attribute access, adding thread-safety, tracking object creation, implementing singletons, and many other tasks. -\index{LBYL} -\item[LBYL] -Look before you leap. This coding style explicitly tests for -pre-conditions before making calls or lookups. This style contrasts -with the \emph{EAFP} approach and is characterized the presence of -many \keyword{if} statements. - \index{mutable} \item[mutable] Mutable objects can change their value but keep their \function{id()}. @@ -280,8 +281,8 @@ See also \emph{immutable}. \index{namespace} \item[namespace] The place where a variable is stored. Namespaces are implemented as -dictionary. There is the local, global and builtins namespace and the -nested namespaces in objects (in methods). Namespaces support +dictionaries. There are the local, global and builtin namespaces +as well asnested namespaces in objects (in methods). Namespaces support modularity by preventing naming conflicts. For instance, the functions \function{__builtin__.open()} and \function{os.open()} are distinguished by their namespaces. Namespaces also aid readability @@ -312,7 +313,7 @@ classes can use Python's newer, versatile features like \index{Python3000} \item[Python3000] -A mythical python release, allowed not to be backward compatible, with +A mythical python release, not required be backward compatible, with telepathic interface. \index{__slots__} @@ -321,7 +322,7 @@ A declaration inside a \emph{new-style class} that saves memory by pre-declaring space for instance attributes and eliminating instance dictionaries. Though popular, the technique is somewhat tricky to get right and is best reserved for rare cases where there are large -numbers of instances in a memory critical application. +numbers of instances in a memory-critical application. \index{sequence} \item[sequence] diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex index 50ab792..aae2763 100644 --- a/Doc/tut/tut.tex +++ b/Doc/tut/tut.tex @@ -2175,7 +2175,7 @@ pattern, list comprehensions can compactly specify the key-value list. \begin{verbatim} >>> dict([('sape', 4139), ('guido', 4127), ('jack', 4098)]) {'sape': 4139, 'jack': 4098, 'guido': 4127} ->>> dict([(x, x**2) for x in (2, 4, 6)) # use a list comprehension +>>> dict([(x, x**2) for x in (2, 4, 6)]) # use a list comprehension {2: 4, 4: 16, 6: 36} \end{verbatim} @@ -4193,6 +4193,7 @@ in this case (the instance will have a single copy of ``instance variables'' or data attributes used by the common base class), it is not clear that these semantics are in any way useful. +%% XXX Add rules for new-style MRO? \section{Private Variables \label{private}} @@ -4201,9 +4202,9 @@ identifiers. Any identifier of the form \code{__spam} (at least two leading underscores, at most one trailing underscore) is textually replaced with \code{_classname__spam}, where \code{classname} is the current class name with leading underscore(s) stripped. This mangling -is done without regard of the syntactic position of the identifier, so +is done without regard to the syntactic position of the identifier, so it can be used to define class-private instance and class variables, -methods, as well as globals, and even to store instance variables +methods, variables stored in globals, and even variables stored in instances. private to this class on instances of \emph{other} classes. Truncation may occur when the mangled name would be longer than 255 characters. Outside classes, or when the class name consists of only underscores, @@ -4232,7 +4233,7 @@ when referencing \code{__dict__} directly. \section{Odds and Ends \label{odds}} Sometimes it is useful to have a data type similar to the Pascal -``record'' or C ``struct'', bundling together a couple of named data +``record'' or C ``struct'', bundling together a few named data items. An empty class definition will do nicely: \begin{verbatim} @@ -4251,7 +4252,7 @@ A piece of Python code that expects a particular abstract data type can often be passed a class that emulates the methods of that data type instead. For instance, if you have a function that formats some data from a file object, you can define a class with methods -\method{read()} and \method{readline()} that gets the data from a string +\method{read()} and \method{readline()} that get the data from a string buffer instead, and pass it as an argument.% (Unfortunately, this %technique has its limitations: a class can't define operations that %are accessed by special syntax such as sequence subscripting or @@ -4261,7 +4262,7 @@ buffer instead, and pass it as an argument.% (Unfortunately, this Instance method objects have attributes, too: \code{m.im_self} is the -object of which the method is an instance, and \code{m.im_func} is the +instance object with the method \method{m}, and \code{m.im_func} is the function object corresponding to the method. @@ -4530,7 +4531,7 @@ wildcard searches: \section{Command Line Arguments\label{command-line-arguments}} -Common utility scripts often invoke processing command line arguments. +Common utility scripts often need to process command line arguments. These arguments are stored in the \ulink{\module{sys}}{../lib/module-sys.html}\ module's \var{argv} attribute as a list. For instance the following output results from @@ -4557,7 +4558,7 @@ module also has attributes for \var{stdin}, \var{stdout}, and messages to make them visible even when \var{stdout} has been redirected: \begin{verbatim} ->>> sys.stderr.write('Warning, log file not found starting a new one') +>>> sys.stderr.write('Warning, log file not found starting a new one\n') Warning, log file not found starting a new one \end{verbatim} @@ -4636,7 +4637,7 @@ for sending mail: >>> import smtplib >>> server = smtplib.SMTP('localhost') >>> server.sendmail('soothsayer@example.org', 'jceasar@example.org', -"""To: jceasar@example.org +"""To: jcaesar@example.org From: soothsayer@example.org Beware the Ides of March. @@ -4660,8 +4661,8 @@ that are time zone aware. >>> now = date.today() >>> now datetime.date(2003, 12, 2) ->>> now.strftime("%m-%d-%y or %d%b %Y is a %A on the %d day of %B") -'12-02-03 or 02Dec 2003 is a Tuesday on the 02 day of December' +>>> now.strftime("%m-%d-%y. %d %b %Y is a %A on the %d day of %B.") +'12-02-03. 02 Dec 2003 is a Tuesday on the 02 day of December.' # dates support calendar arithmetic >>> birthday = date(1964, 7, 31) @@ -4691,8 +4692,8 @@ by modules including: 37 >>> zlib.decompress(t) 'witch which has which witches wrist watch' ->>> zlib.crc32(t) --1438085031 +>>> zlib.crc32(s) +226805979 \end{verbatim} @@ -5219,7 +5220,7 @@ Decimal("0.142857142857142857142857142857142857") \chapter{What Now? \label{whatNow}} Reading this tutorial has probably reinforced your interest in using -Python --- you should be eager to apply Python to solve your +Python --- you should be eager to apply Python to solving your real-world problems. Now what should you do? You should read, or at least page through, the @@ -5382,7 +5383,7 @@ A more capable startup file might look like this example. Note that this deletes the names it creates once they are no longer needed; this is done since the startup file is executed in the same namespace as the interactive commands, and removing the names avoids creating side -effects in the interactive environments. You may find it convenient +effects in the interactive environment. You may find it convenient to keep some of the imported modules, such as \ulink{\module{os}}{../lib/module-os.html}, which turn out to be needed in most sessions with the interpreter. @@ -5474,7 +5475,7 @@ or, better, and so on. No matter how many digits you're willing to write down, the result will never be exactly 1/3, but will be an increasingly better -approximation to 1/3. +approximation of 1/3. In the same way, no matter how many base 2 digits you're willing to use, the decimal value 0.1 cannot be represented exactly as a base 2 @@ -5520,7 +5521,7 @@ turns out that's enough (on most machines) so that \var{x}, but rounding to 16 digits is not enough to make that true. Note that this is in the very nature of binary floating-point: this is -not a bug in Python, it is not a bug in your code either, and you'll +not a bug in Python, it is not a bug in your code either. You'll see the same kind of thing in all languages that support your hardware's floating-point arithmetic (although some languages may not \emph{display} the difference by default, or in all output modes). @@ -5634,7 +5635,7 @@ and recalling that \var{J} has exactly 53 bits (is \code{>= 2**52} but \code{< 2**53}), the best value for \var{N} is 56: \begin{verbatim} ->>> 2L**52 +>>> 2**52 4503599627370496L >>> 2L**53 9007199254740992L |