Re: [Tutor] XML Programs
Glen wrote:
> Thank you for your comprehensive reply. It was very helpful!
> Just to clarify one point, is it not possible to search for a node
> directly in the element / elementTree or do you first need to pull the
> data into a class/dict?
You certainly have other options
>>> catalog.xpath("//catalog/book[contains(title,'Guide')]/title/text()")
["XML Developer's Guide", 'MSXML3: A Comprehensive Guide', 'Visual Studio 7:
A Comprehensive Guide']
>>> catalog.xpath("//catalog/book[starts-
with(author,'Corets')]/title/text()")
['Maeve Ascendant', "Oberon's Legacy", 'The Sundered Grail']
but then the question is whether you want to learn Python or XPath.
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Re: [Tutor] XML Programs
On Apr 21, 2018 09:06, Peter Otten <__pete...@web.de> wrote:
>
> Glen wrote:
>
> > Thank you for your comprehensive reply. It was very helpful!
> > Just to clarify one point, is it not possible to search for a node
> > directly in the element / elementTree or do you first need to pull the
> > data into a class/dict?
>
> You certainly have other options
>
> >>> catalog.xpath("//catalog/book[contains(title,'Guide')]/title/text()")
> ["XML Developer's Guide", 'MSXML3: A Comprehensive Guide', 'Visual Studio 7:
> A Comprehensive Guide']
> >>> catalog.xpath("//catalog/book[starts-
> with(author,'Corets')]/title/text()")
> ['Maeve Ascendant', "Oberon's Legacy", 'The Sundered Grail']
>
> but then the question is whether you want to learn Python or XPath.
Neat! Can you recommend a good resource (book, webpage) for learning Xpath?
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[Tutor] Theory of computation non-emptiness
Hi there, I've been working on code that takes a text file that represents a
specific Deterministic Finite Automata.
The text files are set up in a specific way so that line 1 specifies the number
of states. Line 2 specifies the states (i.e., just a list of the names of the
states, separated by spaces). Line 3 specifies the size of the alphabet. Line 4
specifies the alphabet. Lines 5-7 give the transition function, each row
corresponding to a state (in order specified on line 2) and each column
corresponding to a symbol from the alphabet (in order specified on line 4).
Line 8 specifies the start state. Line 9 specifies the number of final/accept
states. Line 10 specifies the final states.
I have already constructed some functions but next I want to construct a
function determining, for any DFA M, whether or not L(M) = 0 i.e., whether or
not there exists at least one string that is accepted by M. if the language If
L(M) = 0 then I want “language empty” printed. If L(M) != 0; then i need to
print “language non-empty - accepted”, where is replaced by some
string that is accepted by M.
I wanted to use breath first search in order to determine the existence of a
path. Code below is all I've done so far but i'm struggling to find a way in
which to link the states with the transitions in the text file.
hope you can give me some direction and advice.
def NonEmptiness(dic):
dic = openTextFile(dic)
#print(dic['states'].split())
theString = ""
visited = []
queue = dic['states'].split()
newStates = dic['states']
newStatesFinal = re.sub(' ','', newStates)
newAplhabet = re.sub(' ','', dic['alphabet'])
#print(dic['finalStates'][2])
print(newStatesFinal)
#print(newStatesFinal[0])
while queue:
currentState = queue.pop(0)
visited.append(currentState)
#print(visited)
for a in newAplhabet:
if (currentState, a) == (newStatesFinal[0], newAplhabet[0]):
if dic['transitionStates'][0][0] != dic['finalStates'][0] or
dic['finalStates'][2]:
theString + a
else:
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Re: [Tutor] Theory of computation non-emptiness
On 21/04/18 12:50, tracey jones-Francis wrote: > Hi there, I've been working on code I've only glanced at this but one thing jumped out at me: > while queue: > currentState = queue.pop(0) > visited.append(currentState) > #print(visited) > for a in newAplhabet: > if (currentState, a) == (newStatesFinal[0], newAplhabet[0]): > if dic['transitionStates'][0][0] != dic['finalStates'][0] or > dic['finalStates'][2]: This reads to Python like if X != A or B which it parses as if (X != A) or B Is that what you intended? It may be the case but, if so, it's a rather cryptic way of expressing it. HTH -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
