diff options
| -rw-r--r-- | Doc/lib/libpickle.tex | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/Doc/lib/libpickle.tex b/Doc/lib/libpickle.tex index 34898cc..3107114 100644 --- a/Doc/lib/libpickle.tex +++ b/Doc/lib/libpickle.tex @@ -305,14 +305,11 @@ the last location. The \method{__setstate__()} and \method{__getstate__()} methods are used to implement this behavior. \begin{verbatim} -# illustrate __setstate__ and __getstate__ methods -# used in pickling. - class TextReader: - "Print and number lines in a text file." - def __init__(self,file): + """Print and number lines in a text file.""" + def __init__(self, file): self.file = file - self.fh = open(file,'r') + self.fh = open(file) self.lineno = 0 def readline(self): @@ -320,24 +317,23 @@ class TextReader: line = self.fh.readline() if not line: return None - return "%d: %s" % (self.lineno,line[:-1]) + if line.endswith("\n"): + line = line[:-1] + return "%d: %s" % (self.lineno, line) - # return data representation for pickled object def __getstate__(self): - odict = self.__dict__ # get attribute dictionary - del odict['fh'] # remove filehandle entry + odict = self.__dict__.copy() # copy the dict since we change it + del odict['fh'] # remove filehandle entry return odict - # restore object state from data representation generated - # by __getstate__ def __setstate__(self,dict): - fh = open(dict['file']) # reopen file - count = dict['lineno'] # read from file... - while count: # until line count is restored + fh = open(dict['file']) # reopen file + count = dict['lineno'] # read from file... + while count: # until line count is restored fh.readline() count = count - 1 - dict['fh'] = fh # create filehandle entry - self.__dict__ = dict # make dict our attribute dictionary + self.__dict__.update(dict) # update attributes + self.fh = fh # save the file object \end{verbatim} A sample usage might be something like this: @@ -352,9 +348,13 @@ A sample usage might be something like this: '7: class TextReader:' >>> import pickle >>> pickle.dump(obj,open('save.p','w')) +\end{verbatim} - (start another Python session) +If you want to see that \refmodule{pickle} works across Python +processes, start another Python session, before continuing. What +follows can happen from either the same process or a new process. +\begin{verbatim} >>> import pickle >>> reader = pickle.load(open('save.p')) >>> reader.readline() |