Two Plus Two Poker Forums - ** Python Support Thread **

Two Plus Two Poker Forums (https://forumserver.twoplustwo.com/)

- Computer and Technical Help (https://forumserver.twoplustwo.com/48/computer-technical-help/)

- - ** Python Support Thread ** (https://forumserver.twoplustwo.com/48/computer-technical-help/python-support-thread-1007515/)

Re: ** Python Support Thread **

going back to the "don't mess with an iterable while you are iterating through it",

it is perfectly OK (read: safe and not alarming) to do this, right?

Code:

for key, value in somedict.iteritems():

    somedict[key] = somefunction(value)

or (if we have mutable types as values):

Code:

for key, value in somedict.iteritems():

    value.somealteringfunction(key, value)

Re: ** Python Support Thread **

At first, I was doing something similar to:

Code:



while....:

    a = x%y

    if a == 0:

        .....

    else:

        print x

which I guess is the same thing of sorts and serves as a better visual to why the 'test' primitive was in the block instead of outside it.

Not sure how you program without the else blocks. Are you saying you don't specify else or you really don't use it at all? I'm sort of in the habit of using indenting to execute the else opposed to actually writing else. But there are times it is handy. The next two projects are 'brute force algorithms,' which require some else blocks to execute I think, if for nothing else but to return Null values to the main functions. But, eh, I haven't put any effort into much more than a rudimentary start. Hopefully, this one won't take a week to do.

Re: ** Python Support Thread **

Spoilers won't hide the answer from bots by the way. It doesn't do a live call toget the spoiler contents. It just hides or shows a div that's already there.

Re: ** Python Support Thread **

Quote:

Originally Posted by RoundTower (Post 27193974)

going back to the "don't mess with an iterable while you are iterating through it",

it is perfectly OK (read: safe and not alarming) to do this, right?

Code:

for key, value in somedict.iteritems():

    somedict[key] = somefunction(value)

or (if we have mutable types as values):

Code:

for key, value in somedict.iteritems():

    value.somealteringfunction(key, value)

Good question, i've always assumed yes. I generally iterate on the key rather than value though.

Re: ** Python Support Thread **

Yeah that should be fine.

But you don't want to be adding or deleting. That's typically going to be undefined or weird.

Re: ** Python Support Thread **

This code does exactly what I want it to do, but I wonder if there is a simpler solution to this problem. I'm also wondering if there is a different solution to this problem that I didn't catch.

The idea is to find all the values of n via n = 6a + 9b + 20c. I created an ascending list with no repeating values. The program runs pretty slow, but I guess that isn't too surprising since I am running 3 simultaneous loops, checking vs an if, creating a list, sorting the list, then minimizing the list.

Considering the problem set, I could use a smaller value than 150. I ran it with 50 as well, but it is still slow.

Code:



nList = []

for a in range(0,150):

    for b in range(0,150):

        for c in range(0,150):

            n = 6*a + 9*b + 20*c

            if n < 150:

                nList.append(n)

                nList.sort()

                nList = list(set(nList))

print nList

edit to add:

ldo, math ftl?

Code:



nList = []

for a in range(0,10):

    for b in range(0,6):

        for c in range(0,3):

            n = 6*a + 9*b + 20*c

            if n < 50:

                nList.append(n)

                nList.sort()

                nList = list(set(nList))

print nList

Re: ** Python Support Thread **

why are you sorting and uniq'ing during every iteration?

Re: ** Python Support Thread **

Quote:

Originally Posted by tyler_cracker (Post 27209117)

why are you sorting and uniq'ing during every iteration?

I have to check if n, n + 1,... n+5 is possible. According to the theorem, once I have that, then all n + (inf) is possible. I know that the highest possible number n that can't work is 37.

[0, 6, 9, 12, 15, 18, 20, 21, 24, 26, 27, 29, 30, 32, 33, 35, 36, 38, 39, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69]

The plan (for now) is to check all numbers in the list against n, n + 1,... n+5 (which probably creates another for loop somewhere else), then print out 37.

Re: ** Python Support Thread **

that's all gobbledegook to me but even if you really, really need to call

Code:

nList = list(set(nList))

on every iteration, which I'm sure you don't, the expensive sort() operation in the previous line changes absolutely nothing because set() unsorts the list. But really what you should do is make nList a set from the start and call nlist.add(n) instead of your 3 lines.

Re: ** Python Support Thread **

here is the problem set that explains what I am doing.

http://ocw.mit.edu/courses/electrica...ents/pset2.pdf

Re: ** Python Support Thread **

Quote:

Originally Posted by RoundTower (Post 27209892)

that's all gobbledegook to me but even if you really, really need to call

Code:

nList = list(set(nList))

How hard is it for me to highlight and format >> comment to see what happens without sort()?

But, yes, this is good. Thanks.

Re: ** Python Support Thread **

Quote:

Originally Posted by daveT (Post 27209579)

I'm currently working through the OCW Intro to Programming course too. I just did the McNugget problem last week. I'm obviously a Python n00b as well, so take my advice with a grain of salt, but what you're trying to do with lists seems needlessly complicated.

I solved this one pretty easily just brute-forcing the possible combinations and using if/else statements to set the appropriate flags and keep track of a counting variable until I found 6 valid combos in a row.

The code is in a spoiler below in case you don't want to see before you solve it for yourself :

Spoiler:

Re: ** Python Support Thread **

I have a solution, though it probably isn't as correct as yours. This is something I threw together over about 4 hours (which is extremely fast for me). I got a little to married to the list idea, but I'll work on a different solution at a later date.

Spoiler:

Re: ** Python Support Thread **

What's this for:

Quote:

list(set(nList))

You should very, very rarely need to construct two data structures like this. You definitely shouldn't do it multiple times. In your case, why wouldn't you just make nList and noValue set's to start?

In fact: I think you can just leave them as sets and then call max(yourSet) to get the largest number.

Edit: The reason I'm pointing that out is that learning to use the right data structure and avoiding lots of unnecessary conversions between data structures is pretty important. Much more important than trying to get code down to a small size or to figure out the very best algorithm to use.

Re: ** Python Support Thread **

Been trying to learn python for a few months on and off in the free time that I have (very little). This week it finally paid off as I could write a script that eases some of the work I was doing.
Even though it is probably a horrible piece of code from a programmers' view, I was still kinda proud. It's 8 times a similar thing after each other, but each one is dependent on the step before it, so I split it into 8 codeblocks. Is there a way to do that easier?
Rough example: I have x, out of that comes x1 x2 and x3, then I do roughly the same with those and get y11 y12 y13, y21 y22 and y23, and y31/y32/y33.
Is that possible to do in one codeblock without using so many for and if blocks that I tab out of the right side of my screen?

Attached the script btw, some variable names might be weird but they make sense if you know what the subject is about. It basically gets the relevant information out of (in this case) 8 documents and pastes it exactly in the format I want in a new file.

Also, first time dabbling in regexes so it took me a while to figure out all those to get exactly what I wanted.

Spoiler:

Code:

#! /usr/local/bin/python



import re

import os



inputfile='' 

path='C:\\blah\\blah\\'

filelisting=os.listdir(path)

for file in filelisting:

    if file[-3:] == 'dot':

        input=open(path+file)

        inputfile=inputfile+input.read()

        

result=open("C:\\blah\\blah\\results.txt", "w")

result.write('digraph G  {\n')



templinklistresult=open("C:\\blah\\blah\\tempresults.txt", "w")



rank1parents=[]     #store all parents for later use

rank2parents=[]

rank3parents=[]

rank4parents=[]

rank5parents=[]

rank6parents=[]

rank7parents=[]

rank8parents=[]



ideal='000101101110101101'                          #first find ideotype

regex = r'([01]+)\s->\s('+str(ideal)+')(.+)'             #make regex with ideotype

ideotypelinks=re.findall(regex,inputfile)               #do the search





ideoparents=[]

for x in xrange(0,len(ideotypelinks)):    #go through all found ideoparents

    if ideotypelinks[x][0] not in ideoparents: #if-block to remove duplicates

        ideoparents.append(ideotypelinks[x][0])

        templinklistresult.write(ideotypelinks[x][0]+' -> '+ideotypelinks[x][1]+ideotypelinks[x][2]+'\n') #write links to file

        rank1parents.append(ideotypelinks[x][0])

        

        

templinklistresult.write('\n2nd rank\n')        #next generation (one up)



ideoparents1=[]

parents=[]

for x in xrange(0,len(ideoparents)):

    searchword=r'([01]+)\s->\s('+ideoparents[x]+')(.+)' #make regex for each parent

    linklist=re.findall(searchword,inputfile)   #make the list of links/parent

    tempparentslist=[]

    for x in xrange(0,len(linklist)):

        if linklist[x][0] not in parents: #if-block to store parents for

            parents.append(linklist[x][0]) #next generation search start

        if linklist[x][0] not in tempparentslist:   #if-block to remove dups

            tempparentslist.append(linklist[x][0])

            templinklistresult.write(linklist[x][0])    #write all three parts of link 

            templinklistresult.write(' -> ')            #to the file with a newline each 

            templinklistresult.write(linklist[x][1])   #time

            templinklistresult.write(linklist[x][2]+'\n')   

            rank2parents.append(linklist[x][0])

    templinklistresult.write('\n')

    

templinklistresult.write('3rd rank\n')      #next generation (one up)

parentslist=[]

for x in xrange(0,len(parents)):

    searchword=r'([01]+)\s->\s('+parents[x]+')(.+)' #make regex for each parent

    linklist=re.findall(searchword,inputfile)   #make the list of links/parent

    tempparentslist=[]

    for x in xrange(0,len(linklist)):

        if linklist[x][0] not in parentslist: #if-block to store parents for

            parentslist.append(linklist[x][0]) #next generation search start

        if linklist[x][0] not in tempparentslist:   #if-block to remove dups

            tempparentslist.append(linklist[x][0])

            templinklistresult.write(linklist[x][0])    #write all three parts of link 

            templinklistresult.write(' -> ')            #to the file with a newline each 

            templinklistresult.write(linklist[x][1])   #time

            templinklistresult.write(linklist[x][2]+'\n')   

            rank3parents.append(linklist[x][0])

    templinklistresult.write('\n')



templinklistresult.write('4th rank\n')      #next generation (one up)

parents=[]

for x in xrange(0,len(parentslist)):

    searchword=r'([01]+)\s->\s('+parentslist[x]+')(.+)' #make regex for each parent

    linklist=re.findall(searchword,inputfile)   #make the list of links/parent

    tempparentslist=[]

    for x in xrange(0,len(linklist)):

        if linklist[x][0] not in parents: #if-block to store parents for

            parents.append(linklist[x][0]) #next generation search start

        if linklist[x][0] not in tempparentslist:   #if-block to remove dups

            tempparentslist.append(linklist[x][0])

            templinklistresult.write(linklist[x][0])    #write all three parts of link 

            templinklistresult.write(' -> ')            #to the file with a newline each 

            templinklistresult.write(linklist[x][1])   #time

            templinklistresult.write(linklist[x][2]+'\n')   

            rank4parents.append(linklist[x][0])

    templinklistresult.write('\n')



templinklistresult.write('5th rank\n')      #next generation (one up)

parentslist=[]

for x in xrange(0,len(parents)):

    searchword=r'([01]+)\s->\s('+parents[x]+')(.+)' #make regex for each parent

    linklist=re.findall(searchword,inputfile)   #make the list of links/parent

    tempparentslist=[]

    for x in xrange(0,len(linklist)):

        if linklist[x][0] not in parentslist: #if-block to store parents for

            parentslist.append(linklist[x][0]) #next generation search start

        if linklist[x][0] not in tempparentslist:   #if-block to remove dups

            tempparentslist.append(linklist[x][0])

            templinklistresult.write(linklist[x][0])    #write all three parts of link 

            templinklistresult.write(' -> ')            #to the file with a newline each 

            templinklistresult.write(linklist[x][1])   #time

            templinklistresult.write(linklist[x][2]+'\n')   

            rank5parents.append(linklist[x][0])

    templinklistresult.write('\n')

    

templinklistresult.write('6th rank\n')      #next generation (one up)

parents=[]

for x in xrange(0,len(parentslist)):

    searchword=r'([01]+)\s->\s('+parentslist[x]+')(.+)' #make regex for each parent

    linklist=re.findall(searchword,inputfile)   #make the list of links/parent

    tempparentslist=[]

    for x in xrange(0,len(linklist)):

        if linklist[x][0] not in parents: #if-block to store parents for

            parents.append(linklist[x][0]) #next generation search start

        if linklist[x][0] not in tempparentslist:   #if-block to remove dups

            tempparentslist.append(linklist[x][0])

            templinklistresult.write(linklist[x][0])    #write all three parts of link 

            templinklistresult.write(' -> ')            #to the file with a newline each 

            templinklistresult.write(linklist[x][1])   #time

            templinklistresult.write(linklist[x][2]+'\n')   

            rank6parents.append(linklist[x][0])

    templinklistresult.write('\n')   





templinklistresult.write('7th rank\n')      #next generation (one up)

parentslist=[]

for x in xrange(0,len(parents)):

    searchword=r'([01]+)\s->\s('+parents[x]+')(.+)' #make regex for each parent

    linklist=re.findall(searchword,inputfile)   #make the list of links/parent

    tempparentslist=[]

    for x in xrange(0,len(linklist)):

        if linklist[x][0] not in parentslist: #if-block to store parents for

            parentslist.append(linklist[x][0]) #next generation search start

        if linklist[x][0] not in tempparentslist:   #if-block to remove dups

            tempparentslist.append(linklist[x][0])

            templinklistresult.write(linklist[x][0])    #write all three parts of link 

            templinklistresult.write(' -> ')            #to the file with a newline each 

            templinklistresult.write(linklist[x][1])   #time

            templinklistresult.write(linklist[x][2]+'\n')   

            rank7parents.append(linklist[x][0])

    templinklistresult.write('\n')    



templinklistresult.write('8th rank\n')      #next generation (one up)

parents=[]

for x in xrange(0,len(parentslist)):

    searchword=r'([01]+)\s->\s('+parentslist[x]+')(.+)' #make regex for each parent

    linklist=re.findall(searchword,inputfile)   #make the list of links/parent

    tempparentslist=[]

    for x in xrange(0,len(linklist)):

        if linklist[x][0] not in parents: #if-block to store parents for

            parents.append(linklist[x][0]) #next generation search start

        if linklist[x][0] not in tempparentslist:   #if-block to remove dups

            tempparentslist.append(linklist[x][0])

            templinklistresult.write(linklist[x][0])    #write all three parts of link 

            templinklistresult.write(' -> ')            #to the file with a newline each 

            templinklistresult.write(linklist[x][1])   #time

            templinklistresult.write(linklist[x][2]+'\n')   

            rank8parents.append(linklist[x][0])

    templinklistresult.write('\n') 





allparentslist=[]   #to not have any duplicates in parentlist



if len(rank8parents) != 0:

    result.write('''{

                rank = same;\n\t\t''')

for x in xrange(0,len(rank8parents)):

    if rank8parents[x] not in allparentslist:

        allparentslist.append(rank8parents[x])

        searchword=rank8parents[x]+'[^;]*;' #everything up to final /table end

        table=re.search(searchword, inputfile)

        result.write(table.group()+'\n\t\t')



if len(rank8parents) != 0:

    result.write('''}\n\t''')

        

if len(rank7parents) != 0:

    result.write('''{

                rank = same;\n\t\t''')

for x in xrange(0,len(rank7parents)):

    if rank7parents[x] not in allparentslist:

        allparentslist.append(rank7parents[x])

        searchword=rank7parents[x]+'[^;]*;' #everything up to final /table end

        table=re.search(searchword, inputfile)

        result.write(table.group()+'\n\t\t')

        

result.write('''}

        ''')

        

if len(rank6parents) != 0:

    result.write('''{

                rank = same;\n\t\t''')

for x in xrange(0,len(rank6parents)):

    if rank6parents[x] not in allparentslist:

        allparentslist.append(rank6parents[x])

        searchword=rank6parents[x]+'[^;]*;' #everything up to final /table end

        table=re.search(searchword, inputfile)

        result.write(table.group()+'\n\t\t')

        

        

result.write('''}

        ''')

        

if len(rank5parents) != 0:

    result.write('''{

                rank = same;\n\t\t''')

for x in xrange(0,len(rank5parents)):

    if rank5parents[x] not in allparentslist:

        allparentslist.append(rank5parents[x])

        searchword=rank5parents[x]+'[^;]*;' #everything up to final /table end

        table=re.search(searchword, inputfile)

        result.write(table.group()+'\n\t\t')

        

        

result.write('''}

        ''')

        

if len(rank4parents) != 0:

    result.write('''{

                rank = same;\n\t\t''')

for x in xrange(0,len(rank4parents)):

    if rank4parents[x] not in allparentslist:

        allparentslist.append(rank4parents[x])

        searchword=rank4parents[x]+'[^;]*;' #everything up to final /table end

        table=re.search(searchword, inputfile)

        result.write(table.group()+'\n\t\t')

        

        

result.write('''}

        ''')

        

if len(rank3parents) != 0:

    result.write('''{

                rank = same;\n\t\t''')

for x in xrange(0,len(rank3parents)):

    if rank3parents[x] not in allparentslist:

        allparentslist.append(rank3parents[x])

        searchword=rank3parents[x]+'[^;]*;' #everything up to final /table end

        table=re.search(searchword, inputfile)

        result.write(table.group()+'\n\t\t')

        

        

result.write('''}

        ''')

        

if len(rank2parents) != 0:

    result.write('''{

                rank = same;\n\t\t''')

for x in xrange(0,len(rank2parents)):

    if rank2parents[x] not in allparentslist:

        allparentslist.append(rank2parents[x])

        searchword=rank2parents[x]+'[^;]*;' #everything up to final /table end

        table=re.search(searchword, inputfile)

        result.write(table.group()+'\n\t\t')

        

        

result.write('''}

        ''')

        

if len(rank1parents) != 0:

    result.write('''{

                rank = same;\n\t\t''')

for x in xrange(0,len(rank1parents)):

    if rank1parents[x] not in allparentslist:

        allparentslist.append(rank1parents[x])

        searchword=rank1parents[x]+'[^;]*;' #everything up to final /table end

        table=re.search(searchword, inputfile)

        result.write(table.group()+'\n\t\t')



result.write('''}

        ''')        

result.write('''{

                rank = same;\n\t\t''')

    

#paste ideotype table in there

searchword=ideal+'[^;]*;'

table=re.search(searchword, inputfile)

result.write(table.group()+'\n\t\t')





result.write('''Schedulename\n\t\t[shape=egg,fillcolor=gray20,fontcolor=white,fontsize=18,style=filled,label="all"];\n\t}''')



result.write('\n')

templinklistresult.close()

templinklistresult=open("C:\\blah\\blah\\tempresults.txt", "r")

for line in templinklistresult:

    if len(line) >= 10:

        result.write(line)

result.write("}")

Re: ** Python Support Thread **

Quote:

Originally Posted by jjshabado (Post 27216503)

What's this for:

You should very, very rarely need to construct two data structures like this. You definitely shouldn't do it multiple times. In your case, why wouldn't you just make nList and noValue set's to start?

In fact: I think you can just leave them as sets and then call max(yourSet) to get the largest number.

Edit: The reason I'm pointing that out is that learning to use the right data structure and avoiding lots of unnecessary conversions between data structures is pretty important. Much more important than trying to get code down to a small size or to figure out the very best algorithm to use.

Okay, I'll look all this up.

Slick Strawberry: The reason we were using spoilers is so we don't show off the answers to the homework we are doing.

Re: ** Python Support Thread **

I'm using a spoiler because a spoiler gets a scrollbar if the script is too long, don't want my posts to be extremely long and I don't really know a good other way to show off my code.

Re: ** Python Support Thread **

Use the [ code ] tag.

Re: ** Python Support Thread **

Didn't know the code tag also added scrollbars to the code, now I have a code tag in a spoiler tag...

Re: ** Python Support Thread **

You can also use the php tag to get some syntax highlighting. It isn't perfect because it as it is geared towards php, but it does a decent job with any c-style language.

Re: ** Python Support Thread **

What's the best way for iterating over a list while filtering out values?

For example assume I have the following:

Code:

l = [1,None,3]

for x in l:

    if x:

         print 'Do a bunch of stuff'

So I can do:

Code:

l = [1,None,3]

for x in [y for y in l if y]:

    print 'Do a bunch of stuff'

But that still seems a bit wonky. I don't think there are any performance implications but it just doesn't look that great.

Any better ideas?

Re: ** Python Support Thread **

first one looks fine to me.

You can also use

Code:

for x in filter(None, l):

Re: ** Python Support Thread **

in Python 3 I understand you could use

Code:

[print(x) for x i l if x]

which returns a list of None, but has the correct side-effect of printing the non-False values. This won't work in Python 2 because print is not an object. You could wrap whatever you need to do inside the loop in a callable object though.

Re: ** Python Support Thread **

I was wondering how you'd do it without the use of filter (since some people are against that). :)

Your second one won't work for me since my print statement is just standing in for about half a dozen statements and I hate putting a lot of logic inside of a list comprehension.

Re: ** Python Support Thread **

May seem totally out of place, but the only thing I am against is using 'l' and '1' in the same program. People like to use various fonts and some of those fonts aren't going to show the difference between 'l' and '1'. Even with a decent font, it is still easy to mistaken the stuff.