Question

i have a module (a single .py file, actually), with a class called HashedDir.

when i import the file and instanciate 2 instances of that class, when i check the object’s fields they’re always the same, even if the two objects should be different.

Eg:

 h1 = HashedDir('/path/to/dir')  print h1.getList()['files'] # /path/to/dir  h2 = HashedDir('some/other/path')  print h1.getList()['files'] # some/other/path  print h2.getList()['files'] # some/other/path 

Any idea?

This is the class:

from os  import walk from os import path from hashlib import md5 import re  class HashedDir:     '''     A list of files with associated md5 hashes generated retrieving thou     a recursive walk in the directory tree starting from a provided root     directory. Also stores the dirs in each dir     '''      #  {'files': [     #    ('/path/to/file1', '52bc309e11259af15e4623c7a0abc28c'),     #    ('/path/to/file2', '52bc309e11259af15e4623c7a0abc28c'),     #    ('/path/to/dir/file3', '52bc309e11259af15e4623c7a0abc28c')     #   ],     #   'dirs': ['/path/to/dir1', '/path/to/dir2']     #  }     fileList = {'files': [], 'dirs': []}     ignoreList = []      def __init__(self, rootDir, ignoreList=[]):         '''         ignoreList is a list of regular expressions. If a file or a dir matches         that regular expression, don't count it         '''         self.ignoreList = ignoreList          for dirpath, dirnames, filenames in walk(rootDir):             for fileName in filenames:                 completeName = path.join(dirpath,fileName)                 hash = md5(open(completeName).read()).hexdigest()                 relativePath = self._relativePath(completeName, rootDir)                 if not self._toBeIgnored(relativePath):                     self.fileList['files'].append((relativePath, hash))             for dirName in dirnames:                 completeName = path.join(dirpath, dirName)                 relativePath = self._relativePath(completeName, rootDir)                 if not self._toBeIgnored(relativePath):                     self.fileList['dirs'].append(relativePath)      def _relativePath(self, path, base):         return path.replace(base, '')      def _toBeIgnored(self, path):         for regex in self.ignoreList:             if re.compile(regex).search(path) != None:                 return True         return False      def getList(self):         return self.fileList 

Thanks in advance

Answer 1

There are two kinds of variables in a class:

• class variables, defined at the class level, and common to all instances

• instance variables, defined within a class method (usually __init__) and qualified by the instance (usually self.).

Example

class SomeClass( object ):     classVariable = 0     def __init__( self ):         self.instanceVariable= 0 

The variable named classVariable is part of the class, common to all instances. Because of the way Python does search, it’s available as a member of self.classVariable, as well as SomeClass.classVariable.

The variable named instanceVariable is part of the instance (self.) and is unique to each instance.

Note. There’s a third kind, global, but that’s not what you’re asking about.