python backports for some methods

Question

Is there any backport for the following methods to work with python 2.4:

any, all, collections.defaultdict, collections.deque

Answer 1

Well, at least for any and all it's easy:

def any(iterable):
    for element in iterable:
        if element:
            return True
    return False

def all(iterable):
    for element in iterable:
        if not element:
            return False
    return True

deque is already in 2.4.

As for defaultdict, I guess you can emulate that easily with setdefault().

Quoting from Alex Martelli`s (and others') highly recommended Python Cookbook:

This is what the setdefault method of dictionaries is for. Say we’re building a word-to-page-numbers index, a dictionary that maps each word to the list of page numbers where it appears. A key piece of code in that application might be:

def addword(theIndex, word, pagenumber):
    theIndex.setdefault(word, [ ]).append(pagenumber)

This code is equivalent to more verbose approaches such as:

def addword(theIndex, word, pagenumber):
    if word in theIndex:
        theIndex[word].append(pagenumber)
    else:
        theIndex[word] = [pagenumber]

and:

def addword(theIndex, word, pagenumber):
    try:
        theIndex[word].append(pagenumber)
    except KeyError:
        theIndex[word] = [pagenumber]