Often, I am building an array by iterating through some data, e.g.:
my_array = []
for n in range(1000):
# do operation, get value
my_array.append(value)
# cast to array
my_array = array(my_array)
I find that I have to first build a list and then cast it (using "array") to an array. Is there a way around these? all these casting calls clutter the code... how can I iteratively build up "my_array", with it being an array from the start?
thanks.
What's a correct and good way to implement hash()?
I am talking about the function that returns a hashcode that is then used to insert objects into hashtables aka dictionaries.
As hash() returns an integer and is used for "binning" objects into hashtables I assume that the values of the returned integer should be uniformly distributed for common data (to minimize collisions).
What's a good practice to get such values? Are collisions a problem?
In my case I have a small class which acts as a container class holding some ints, some floats and a string.
I coded in Java for many years and after i saw this beauty:
with open("spam.egg") as f:
for line in f:
print line
i said to myself, i can't use Java's StreamVerboseCrapByteOpenBuffer stuff anymore.
What's your snippet?
For instance, if I have:
C:\42\main.py
and
C:\42\info.txt
and I want to read info.txt from main.py, I have to input "C:\42\info.txt" instad of just "info.txt".
Is it supposed to be like that?
If not, how can I fix it?
Suppose I have a dictionary, and it's nested with dictionaries inside.
I want to join all the values of that dictionary, recursively?
' '.join(d.values())
That works if there are no nests.
msg = EmailMessage(subject, body, from_email, [to_email])
msg.content_subtype = "html"
msg.send()
This is how I send an email in Django.
But what if I want to open a text file and take into account all its line breaks and tabs. I want to take the body of the text file (with line breaks \n) and email it as text of the "body".
I'm working on a project and it seems that every time someone checks out the project from source control to build it on their local box they have issues building because references are no longer resolved.
I can't figure out if it's a configuration issues or a Visual Studio 2008 issue. Is anyone else having this problem? If so, is there something you can do to fix this issue?
Note: it might have something to do with explicit paths to the DLLs being referenced or how they are referenced ... I'm not quite sure.
I've made a couple of scripts. One is a stock screener that can search through every stock. Another creates a heatmap that tells you what's performed well and badly over the past day. They aren't really that useful, just did them to work on my programming skills. I was able to throw some SQL in my scripts too. Would you call that intermediate? Thanks? How do you guys list your programming skills on your resume? Maybe there's a better way of putting it on my resume than "intermediate" or "beginner."
I am looking at some code that has a lot of sort calls using comparison functions, and it seems like it should be using key functions.
If you were to change seq.sort(lambda x,y: cmp(x.xxx, y.xxx)), which is preferable:
seq.sort(key=operator.attrgetter('xxx'))
or:
seq.sort(key=lambda a:a.xxx)
I would also be interested in comments on the merits of making changes to existing code that works.
The id() inbuilt function gives...
an integer (or long integer) which is guaranteed to be unique and constant for this object during its lifetime.
The is operator, instead, gives...
object identity
So why is it possible to have two objects that have the same id but return False to an is check? Here is an example:
>>> class Test():
... def test():
... pass
>>> a = Test()
>>> b = Test()
>>> id(a.test) == id(b.test)
True
>>> a.test is b.test
False
A more troubling example: (continuing the above)
>>> b = a
>>> b is a
True
>>> b.test is a.test
False
>>> a.test is a.test
False
Hi, i was curious if there is some sort of way to change the look and feel of wxpython to something that is more standardized. I am writing a small application for windows and mac os x. And i noticed that Mac formats the layout and look of my application pretty terribly. I looked around online and could not find anything. Any ideas?
In NumPy functions, there are often initial lines that do checking of variable types, forcing them to be certain types, etc. Can someone explain the point of these lines? What does subtracting a value from itself do?
t,w = asarray(t), asarray(duty)
w = asarray(w + (t-t))
t = asarray(t + (w-w))
In Django, I have a model object in a list.
[object, object, object]
Each object has ".name" which is the title of the thing.
How do I sort alphabetically by this title?
This doesn't work:
catlist.sort(key=lambda x.name: x.name.lower())
I have a bunch of HTML files in HTML folder. Those HTML files have unicode characters which I solved by using filter(lambda x: x in string.printable, line). Now how do I write the changes back to the original file? What is the best way of doing it? Each HTML file is of 30 kb in size.
1 import os, string
2
3 for file in os.listdir("HTML/"):
4 print file
5 myfile = open('HTML/' + file)
6 fileList = myfile.readlines()
9 for line in fileList:
10 #print line
11 line = filter(lambda x: x in string.printable, line)
12 myfile.close()
I'm adding some new bits to one of the lines in a text file and then writing it along with the rest of the lines in the file to a new file. Referring to the if statement, I that to be all on the same line:
x = 13.55553e9
y = 14.55553e9
z = 15.55553e9
infname = 'afilename'
outfname = 'anotherone'
oldfile = open(infname)
lnum=1
for line in oldfile:
if (lnum==18):
line = "{0:.2e}".format(x)+' '+line+' '+"{0:.2e}".format(y)+' '+ {0:.2e}".format(z)
newfile = open(outfname,'w')
newfile.write(line)
lnum=lnum+1
oldfile.close()
newfile.close()
but y and z are being written on the line below the rest of it. What am I missing here?
class MyController(BaseController):
def index(self):
# Return a rendered template
#return render('/test.mako')
# or, return a response
return ''
Why does the function "index" have "self"?
I got this code from Pylons controller