reduce versus recursion? what am I missing...

Warren Postma embed at geocities.com
Fri Apr 7 17:57:37 CEST 2000


# I am trying to figure out why function d (recursive) and e (reduce)
# DON'T do the SAME thing:

def d(*tup):
    "why doesn't this work?"
    if len(tup)>1:
        return d(tup[1:])+abs(tup[0]-tup[1])
    else:
        return 0

l = (1,3,5,7,9)

def e(*tup):
    "it works"
    return reduce(lambda x,y:abs(x-y),tup,0)

print "--- test:"
print "recursion: ",apply(d,l)
print "reduce:    ",apply(e,l)

#---
#Warren
#
# output:
#--- test:
#recursion:  2     ( appears not to actually be recursing more than 1
level!!!???)
#reduce:     5






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