Question

I thinl there is problem with ps3_template.py???why?

Answer 1

I am also having trouble at the same place. My subStringMatchExact and constrainedMatchPair functions seem to give the correct output, but when I use the subStringMatchOneSub function provided in ps3_template.py I recieve no matches. Is there an error in the provided code?

Answer 2

I am going to post the code for the functions I created below:

def subStringMatchExact(target,key):
bookmark=0
location=()
#While the find function does not fail to find a value
while bookmark!=-1:
#Store the index of the first match in bookbark.
bookmark=find(target,key,bookmark)
#Add bookmark to a tuple
location=location+(bookmark,)
#Find the next value of bookmark here so that if it is -1 we can stop before looping again.
bookmark=find(target,key,bookmark+1)
return location

def constrainedMatchPair(firstMatch,secondMatch,length):
listmatch=()
for n in range(0,len(firstMatch)):
for k in range(0,len(secondMatch)):
if firstMatch[n]+length+1==secondMatch[k]:
listmatch=listmatch+(firstMatch[n],)
return listmatch

Answer 3

After putting some more work into this problem, I found my mistake. Perhaps this will help you too welldone_boy. The function given in the ps3_template asks you to input the key first, then the target (key, target). The previous functions that we created had us input in the reverse order (target,key).

Answer 4

I was able to complete the problem set last week with the function subStringMatchOneSub as defined in the template, there is no problem with it.

Looking through your code I see a potential error your function constrainedMatchedPair. Be careful when using range(0,len(x)) in your loops, as the range function will cut off your last item:

Yours:
for n in range(0,len(firstMatch)):

My suggestion:
for n in firstMatch:

Also, I suggest using pastepin.com for code sharing.

Answer 5

oocks,

It is true that the parameters are reversed in subStringMatchOneSub. Good catch.

Answer 6

ohh good catch !I didn't noticed that..

Answer 7

when we use find(target,'') #empty string# it returns zero(0) but when we apply it(empty str) to subStringMatchExact we kinda run into infinite loop is there anyway to fix that bug?