Why does way_1() obtain the correct list but way_2() gets an empty list?
Hello group! This is probably a silly newbie mistake but consider the following program: import libsbml def getSBMLModel(biomodel_path): reader = libsbml.SBMLReader() sbml_doc = reader.readSBML(biomodel_path) sbml_model = None if sbml_doc.getNumErrors() > 0: print 'I couldn\'t read the file %s!' % biomodel_path return None else: sbml_model = sbml_doc.getModel() return sbml_doc.getModel() # None if file couldn't be opened def way_1(biomodel_path): reader = libsbml.SBMLReader() sbml_doc = reader.readSBML(biomodel_path) sbml_model = sbml_doc.getModel() if sbml_model == None: return l = sbml_model.getListOfSpecies() print 'In way_1(): Got list %s with the length %i' % (l, len(l)) def way_2(biomodel_path): sbml_model = getSBMLModel(biomodel_path) if sbml_model == None: return l = sbml_model.getListOfSpecies() print 'In way_2(): Got list %s with the length %i' % (l, len(l)) file = '../BIOMD03.xml' # Changing the order of these two calls doesn't help, only way_1() works. way_1(file) way_2(file) When run, the output is: In way_1(): Got list type 'ListOfSpecies *' at 0x291c8bc> > with the length 3 In way_2(): Got list type 'ListOfSpecies *' at 0x27fb57c> > with the length 0 I don't get it way the species list obtained in way_2() is empty? For the input file I'm using I should be getting 3 species for the test file I'm using. I'm sorry that this program uses a third-party library which is probably unknown to many, but since I make a lot of newbie mistakes I thought that it's very likely that this is a issue in how I use python, not a library issue. To compensate somewhat I tried to show my entire test program and its output and make that test program as clear as possible. So if anyone knows why I get this behavior I would like to hear it and I will have learned something today too! :) - WP -- http://mail.python.org/mailman/listinfo/python-list
Can I replace this for loop with a join?
Hello, I have dictionary {1:"astring", 2:"anotherstring", etc}
I now want to print:
"Press 1 for astring"
"Press 2 for anotherstring" etc
I could do it like this:
dict = {1:'astring', 2:'anotherstring'}
for key in dict.keys():
print 'Press %i for %s' % (key, dict[key])
Press 1 for astring
Press 2 for anotherstring
but can I use a join instead?
Thanks for any replies!
- WP
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My very first python program, need help
Hello, below is my very first python program. I have some questions
regarding it and would like comments in general. I won't be able to get
my hands on a good python book until tomorrow at the earliest. The
program takes a string and sums all numbers inside it. I'm testing with
the following string: "123xx,22! p1" which should yield a sum of 123 +
22 + 1 = 146. My solution to this exercise was to write a function that
takes a string and splits it into a list of numbers and then I will sum
up the numbers in the list. In fact, I wrote two versions of this
function: One uses a for loop to replace all characters that is not a
digit and not a space with a space. That should leave me with the
numbers intact and with only spaces separating these numbers. Then I
call split to get a list of numbers (here I discovered I must not use a
sep equal to ' ' or the returned list would contain empty strings as
well). This is calculate_sum_1() and look at the comment in the code to
see what worries me there. The second one uses regular expressions and
the problem I have with that is that I get a list of containing not just
the numbers but empty strings as well. I'm working around that in my
loop that sums the numbers but it would be better to not have these
empty string in the list in the first place. Here's the code:
import re
def calculate_sum_1(str):
for c in str:
if c.isdigit() == False and c != ' ':
# That we assign to the variable we're looping over worries
me...
str = str.replace(c, ' ')
mylist = str.split()
print "(for loop version) mylist after replace() and split() = ",
mylist
sum = 0
for item in mylist:
sum += long(item)
return sum
def calculate_sum_2(str):
#print "In replace_nondigits_2(), str = ", str
p = re.compile('[^0-9]')
mylist = p.split(str)
print "(regex version) mylist after calling split(): ", mylist
sum = 0
for item in mylist:
if item.isdigit():
sum += long(item)
return sum
str = "123xx,22! p1" # Sum = 123 + 22 + 1 = 146
print "str = ", str
print "calculate_sum_1(str): %d" % calculate_sum_1(str)
print "calculate_sum_2(str): %d" % calculate_sum_2(str)
The output when run is:
str = 123xx,22! p1
(for loop version) mylist after replace() and split() = ['123', '22', '1']
calculate_sum_1(str): 146
(regex version) mylist after calling split(): ['123', '', '', '22', '',
'', '1']
calculate_sum_2(str): 146
Hope I made some sense and thanks for reading!
- Eric (WP)
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Re: My very first python program, need help
Wojtek Walczak wrote: [snip] Thanks for all your help. I've incorporated your suggestions and moved on to my next program. See new thread. :) - Eric (WP) -- http://mail.python.org/mailman/listinfo/python-list
Second python program: classes, sorting
Hello, here are some new things I've problems with. I've made a program that opens and reads a text file. Each line in the file contains a name and a score. I'm assuming the file has the correct format. Each name-score pair is used to instantiate a class Score I've written. This works fine, but here's my problem: After reading the file I have list of Score objects. Now I want to sort them in descending order. But no matter how I write my __cmp__ the order remains unchanged. I've determined that __cmp__ is called but it's only called twice for three list elements, isn't that odd? Complete program: class Score: def __init__(self, name_, score_): self.name = name_ self.score = score_ def __str__(self): return "Name = %s, score = %d" % (self.name, self.score) def __cmp__(self, other): print "in __cmp__" return self.score >= other.score name = "" score = 0 # End class Score filename = "../foo.txt"; try: infile = open(filename, "r") except IOError, (errno, strerror): print "IOError caught when attempting to open file %s. errno = %d, strerror = %s" % (filename, errno, strerror) exit(1) lines = infile.readlines() infile.close() lines = [l.strip() for l in lines] # Strip away trailing newlines. scores = [] for a_line in lines: splitstuff = a_line.split() scores.append(Score(splitstuff[0], int(splitstuff[1]))) scores.sort() for a_score in scores: print a_score Test file contents: Michael 11 Hanna 1337 Lena 99 Output: in __cmp__ in __cmp__ Name = Michael, score = 11 Name = Hanna, score = 1337 Name = Lena, score = 99 What am I doing wrong here? - Eric (WP) -- http://mail.python.org/mailman/listinfo/python-list
Re: Second python program: classes, sorting
WP wrote: Solved the problem, see below... Hello, here are some new things I've problems with. I've made a program that opens and reads a text file. Each line in the file contains a name and a score. I'm assuming the file has the correct format. Each name-score pair is used to instantiate a class Score I've written. This works fine, but here's my problem: After reading the file I have list of Score objects. Now I want to sort them in descending order. But no matter how I write my __cmp__ the order remains unchanged. I've determined that __cmp__ is called but it's only called twice for three list elements, isn't that odd? Complete program: class Score: def __init__(self, name_, score_): self.name = name_ self.score = score_ def __str__(self): return "Name = %s, score = %d" % (self.name, self.score) def __cmp__(self, other): print "in __cmp__" return self.score >= other.score name = "" score = 0 # End class Score filename = "../foo.txt"; try: infile = open(filename, "r") except IOError, (errno, strerror): print "IOError caught when attempting to open file %s. errno = %d, strerror = %s" % (filename, errno, strerror) exit(1) lines = infile.readlines() infile.close() lines = [l.strip() for l in lines] # Strip away trailing newlines. scores = [] for a_line in lines: splitstuff = a_line.split() scores.append(Score(splitstuff[0], int(splitstuff[1]))) scores.sort() for a_score in scores: print a_score Test file contents: Michael 11 Hanna 1337 Lena 99 Output: in __cmp__ in __cmp__ Name = Michael, score = 11 Name = Hanna, score = 1337 Name = Lena, score = 99 What am I doing wrong here? - Eric (WP) I solved it, I rewrote __cmp__ to: def __cmp__(self, other): if self.score == other.score: return cmp(self.name, other.name) else: return cmp(other.score, self.score) This sorts so that score goes from highest to lowest. If two person have the same score, I sort on names in alphabetical order. The following text file: Michael 11 Hanna 1337 Lena 99 Anna 99 yields (just as I want): Name = Hanna, score = 1337 Name = Anna, score = 99 Name = Lena, score = 99 Name = Michael, score = 11 - Eric (WP) -- http://mail.python.org/mailman/listinfo/python-list
