Re: [Tutor] Fwd: Puzzle - Next Step to our interviewing process - Pramati Technologies!
Sunil Tech writes: > I need the python program This is a resource for tutoring, not for others to write your program. Please approach this as an opportunity to do the work yourself *while* learning. It's still you that needs to write the program. -- \ “If I held you any closer I would be on the other side of you.” | `\ —Groucho Marx | _o__) | Ben Finney ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fwd: Puzzle - Next Step to our interviewing process - Pramati Technologies!
Hi, On 15 April 2014 15:49, Sunil Tech wrote: > Hi Danny, > > > Thank you for replying.. > > I need the python program which takes the attached csv & on running the > program which will give me the results as That is still not a question. It's a requirements statement. I felt tempted to point out to you that this is not a freelancer board where you get to post your software requirements and then we go and develop your software for you for free, but seeing as you obviously must know this already and presumably are actually in the process of trying to learn Python and are presumably using this apparent interview question as an interesting learning problem, I'll instead ask you to clarify how far you've gotten and where exactly you're stuck in developing a solution? We'll try and help you along and answer specific concrete questions about problems you're having. (Please provide code and full error messages including stack traces where relevant.) If you're stuck even just getting started, try breaking down the problem into smaller sub problems and solving them first, for example it's obvious from the descriptions you'll need to be able to: a) Interpret command line parameters to pick up the menu file name and products required b) Read a/the menu file into memory c) Perform some sort of search/scan of the list of menu items to return a list of restaurants carrying all the required items d) Evaluate the total costs for the items for each of the candidate restaurants to find the cheapest one e) Output/Print the result in the required format Do you have an idea/know how you might tackle each of these sub-tasks? If not, do you have an idea where to start looking to learn what you might use? Walter ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fwd: Puzzle - Next Step to our interviewing process - Pramati Technologies!
Hi Danny, Thank you for replying.. I need the python program which takes the attached csv & on running the program which will give me the results as Data File data.csv 1, 4.00, burger 1, 8.00, tofu_log 2, 5.00, burger 2, 6.50, tofu_log Program Input program data.csv burger tofu_log Expected Output => 2, 11.5 --- Data File data.csv 3, 4.00, chef_salad 3, 8.00, steak_salad_sandwich 4, 5.00, steak_salad_sandwich 4, 2.50, wine_spritzer Program Input program data.csv chef_salad wine_spritzer Expected Output => nil (or null or false or something to indicate that no matching restaurant could be found) --- Data File data.csv 5, 4.00, extreme_fajita 5, 8.00, fancy_european_water 6, 5.00, fancy_european_water 6, 6.00, extreme_fajita, jalapeno_poppers, extra_salsa Program Input program data.csv fancy_european_water extreme_fajita Expected Output => 6, 11.0 On Tue, Apr 15, 2014 at 8:05 PM, Danny Yoo wrote: > So, what is your question? > ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fwd: Puzzle - Next Step to our interviewing process - Pramati Technologies!
So, what is your question? ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] questions when define a class
Qianyun Guo wrote:
> Hi all, I am trying to get a suffix tree from a string. I use three
> classes, Node, Edge, SuffixTree. I have two questions when implementing:
>
> 【1】
>
a = Edge(1,2,3,4)
>
a.length
>
> 1
> if I remove '@property' in my code, it returns as below:
>
a = Edge(1,2,3,4)
>
a.length
>
>
>
a.length()
>
> 1
>
>
>
> I don't really understand the differences w/ @property, and the
> differences of a.length and a.length(), could you explain?
Properties are a way to calculate attributes:
> @property
> def length(self):
> return self.last_char_index - self.first_char_index
In client code
obj.length
looks like an attribute, but does a calculation under the hood. This is
particularly useful to keep a changing interface compatible to prior
versions:
version 1, everybody uses cartesian coordinates:
class Point:
def __init__(self, x, y):
self.x = x
self.y = y
version 2, polar coordinates are so much better ;)
class Point:
def __init__(self, r, phi):
self.r = r
self.phi = phi
@property
def x(self):
return self.r * math.cos(self.phi)
@property
def y(self):
return self.r * math.sin(self.phi)
Thanks to properties our new point can be passed to functions that expect
cartesian coords. Without properties we'd either end up writing a trivial
wrapper
def get_x(self):
return self.x
for every attribute (the Java way) and never use attributes directly or we'd
have to change all occurences of point.x to point.x().
> 【2】
>
> In SuffixTree, I define two functions, _get_str_from_edge,
> _get_str_from_node, the latter depend on the first one (please see my
> code). Then I have this problem:
>
a = SuffixTree('abcd')
>
a._get_str_from_edge(a.edges[(0,1)])
>
> 'abcd$'
>
a._get_str_from_node(0,1)
>
> TypeError: _get_str_from_edge() takes exactly 2 arguments (3 given)
>
> Could you tell me what's wrong here?
> def _get_str_from_node(self, source_node_index, dest_node_index):
> return self._get_str_from_edge(self,
> self.edges[(source_node_index,
> \
> dest_node_index)])
self._get_str_from_edge
gives you a "bound method", i. e. one that already knows about self. Invoke
it as
return self._get_str_from_edge(
self.edges[(source_node_index,
dest_node_index)])
By the way, the backslash is not necessesary as long as there are open
parens. Preferred:
(1 + # no backslash
2)
Obsolete alternative:
1 + \
2
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[Tutor] questions when define a class
Hi all, I am trying to get a suffix tree from a string. I use three
classes, Node, Edge, SuffixTree. I have two questions when implementing:
【1】
>>> a = Edge(1,2,3,4)
>>> a.length
1
if I remove '@property' in my code, it returns as below:
>>> a = Edge(1,2,3,4)
>>> a.length
>>> a.length()
1
I don't really understand the differences w/ @property, and the differences
of a.length and a.length(), could you explain?
【2】
In SuffixTree, I define two functions, _get_str_from_edge,
_get_str_from_node, the latter depend on the first one (please see my
code). Then I have this problem:
>>> a = SuffixTree('abcd')
>>> a._get_str_from_edge(a.edges[(0,1)])
'abcd$'
>>> a._get_str_from_node(0,1)
TypeError: _get_str_from_edge() takes exactly 2 arguments (3 given)
Could you tell me what's wrong here?
below is my code, __repr__ are removed for convenience.
###
class Node:
def __init__(self, parent_node):
self.suffix_node = -1
self.parent = parent_node
self.children = []
def add_child(self, child_node_index):
self.children.append(child_node_index)
class Edge:
def __init__(self, first_char_index, last_char_index,\
source_node_index, dest_node_index):
self.first_char_index = first_char_index
self.last_char_index = last_char_index
self.source_node_index = source_node_index
self.dest_node_index = dest_node_index
@property
def length(self):
return self.last_char_index - self.first_char_index
class SuffixTree:
def __init__(self, string):
self.string = string+'$'
self.N = len(self.string)
self.nodes = []
self.num_nodes = 0
self.edges = {}
#initialize two node tree
root = Node(-1)
root.suffix_node = -1
self._add_node(root)
leaf = Node(0)
leaf.suffix_node = 0
self._add_node(leaf)
self.nodes[0].add_child(1)
edge = Edge(0, self.N, 0, 1)
self._add_edge(edge)
def _get_str_from_edge(self, edge):
return self.string[edge.first_char_index : edge.last_char_index]
def _get_str_from_node(self, source_node_index, dest_node_index):
return self._get_str_from_edge(self, self.edges[(source_node_index,
\
dest_node_index)])
def _add_node(self, node):
self.nodes.append(node)
self.num_nodes += 1
def _add_edge(self, edge):
self.edges[(edge.source_node_index, edge.dest_node_index)] = edge
self.nodes[edge.source_node_index].add_child(edge.dest_node_index)
self.nodes[edge.dest_node_index].parent = edge.source_node_index
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Re: [Tutor] Quick Question
Hi Victoria, On Tue, Apr 15, 2014 at 12:06:13AM -0500, Victoria Kuritza wrote: > How can I search in a corpus for three or more occurrences of > capitalized words in a line? What would I input as my search? I'm afraid that question is a bit *too* quick. What are you using for search? My guess is that you're using NLTK, but I'm afraid I don't know a lot about that. It would help if you showed us what you're using to search for a single capitalized word. Regards, Steve ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] reading a csv file
yes Alan, what you said is true.
Thank you.
On Tue, Apr 15, 2014 at 1:40 PM, Alan Gauld wrote:
> On 15/04/14 07:06, Sunil Tech wrote:
>
>> Hi,
>>
>> #!/usr/bin/python
>>
>> import csv
>> import sys
>>
>> def main():
>> cr = csv.reader(open("data.csv","rb"))
>> for row in cr:
>> print row
>>
>
> when i run this...
>>
>>
>> cr = csv.reader(open("data.csv","rb"))
>> AttributeError: 'module' object has no attribute 'reader'
>>
>>
> The most common cause of this error is that you have
> created a file called csv.py which is masking the
> library module.
>
> Could that be the case here?
>
>
> --
> Alan G
> Author of the Learn to Program web site
> http://www.alan-g.me.uk/
> http://www.flickr.com/photos/alangauldphotos
>
> ___
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Re: [Tutor] Quick Question
On 15/04/2014 06:06, Victoria Kuritza wrote: How can I search in a corpus for three or more occurrences of capitalized words in a line? What would I input as my search? Cheers, Victoria K. What does your code currently look like? What problems are you actually having? Last and by no means least, where is the Python question here? -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Quick Question
How can I search in a corpus for three or more occurrences of capitalized words in a line? What would I input as my search? Cheers, Victoria K. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Python & algorithms (Lang line simplification algorithm)
Okay I'll try. What the main job is to do an algorithm which simples a
line. Algorithm deletes points which are unnecessary accurate according to
tolerance distance user gives.
>> I started by converting the pseudocode I had to python.
Pseudocode:
http://web.cs.sunyit.edu/~poissad/projects/Curve/about_algorithms/lang
1. function lang(PointList[], Tolerance)
2. key=0
3. endP= PointList.length-1
4. do {
5. endP= PointList.length-1
6. if (key+1 != endP) // If there are intermediate points
7. line= new Line( PointList[key], PointList[endP])
8. /* Find the point with the furthest perpendicular distance */
9. maxIndex= key+1
10. maxD= perpendicularDistance(line, PointList[maxIndex])
11. for (i=maxIndex+1; i maxD)
14. maxIndex=i
15. maxD=d
16. if (maxD > Tolerance)
17. endP--;
18. else
19. for (i=key+1; i> Still I have problems with perpendicular distance and creating a line
>> with python.
What I mean by creating a line is what Alan answered "checking
distances/intersections
etc only requires the math model." I need the mathematical model not a
picture/graph. I'll try move forward with Bens suggestion of ‘math’ module
which probably help me with both mathematical line model between two points
and its distance between the intermediate points.
> http://docs.python.org/3/library/math.html#trigonometric-functions>.
Here is a picture of the lang algorithm, where you can see distance of
interest by purple
http://psimpl.sourceforge.net/lang.html.
I'll ask later if I can't get this work.
Cheers!
2014-04-15 3:23 GMT+03:00 Ben Finney :
> Laura Kauria writes:
>
> > Thanks a lot for all the help! I got the courage to start at least..
>
> Congratulations! Courage is a necessary ingredient when starting :-)
>
> Could you please avoid top-posting, and instead use interleaved style
> https://en.wikipedia.org/wiki/Posting_style#Interleaved_style> for
> your replies, so the conversation is in a natural order.
>
> > I started by converting the pseudocode I had to python.
>
> If it's short and simple, please post it here so we can discuss it in
> context.
>
> > Still I have problems with perpendicular distance and creating a line
> > with python.
> > I need to create a line between two points and then check what is the
> > distance between a line and intermediate points which were between lines
> > start and end point. If someone could help me with this? I could not
> > understand can I do this without math library or not?
>
> The ‘math’ module in the standard library has trigonometric functions
> http://docs.python.org/3/library/math.html#trigonometric-functions>.
> If you have co-ordinate data and know how to use trigonometry, then
> those functions will do what you expect.
>
> --
> \“If I melt dry ice, can I swim without getting wet?” —Steven |
> `\Wright |
> _o__) |
> Ben Finney
>
> ___
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>
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Re: [Tutor] reading a csv file
On 15/04/14 07:06, Sunil Tech wrote:
Hi,
#!/usr/bin/python
import csv
import sys
def main():
cr = csv.reader(open("data.csv","rb"))
for row in cr:
print row
when i run this...
cr = csv.reader(open("data.csv","rb"))
AttributeError: 'module' object has no attribute 'reader'
The most common cause of this error is that you have
created a file called csv.py which is masking the
library module.
Could that be the case here?
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.flickr.com/photos/alangauldphotos
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