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Getting number of elements in an iterator in Python
...ber of items.
"""
counter = itertools.count()
deque(itertools.izip(iterable, counter), maxlen=0) # (consume at C speed)
return next(counter)
(For Python 3.x replace itertools.izip with zip).
share
...
How to get all subsets of a set? (powerset)
...ge(x)]
for i in range(1 << x):
yield [ss for mask, ss in zip(masks, s) if i & mask]
And then the test code would look like this, say:
print(list(powerset([4, 5, 6])))
Using yield means that you do not need to calculate all results in a single piece of memory. Precalculatin...
Post-install script with Python setuptools
...
Note: The solution below only works when installing a source distribution zip or tarball, or installing in editable mode from a source tree. It will not work when installing from a binary wheel (.whl)
This solution is more transparent:
You will make a few additions to setup.py and there is no n...
What does enumerate() mean?
... # return an iterator that adds a counter to each element of it
return zip(count(start), it)
and
def enumerate(it, start=0):
count = start
for elem in it:
yield (count, elem)
count += 1
The actual implementation in C is closer to the latter, with optimisations to reu...
Best practices for storing postal addresses in a database (RDBMS)?
...locality => Dependent locality (unused)
postal_code => Postal code / ZIP Code
thoroughfare => Street address
premise => Apartment, Suite, Box number, etc.
sub_premise => Sub premise (unused)
A lessons I've learned:
Don't store anything numerically.
Store country and administrative...
App Inventor 2 中的响应式设计 · App Inventor 2 中文网
...路 在线 客服 扫码添加客服咨询 我要 分享 扫码分享到朋友圈 顶部 var qrcode = new QRCode("qrcode", { text: window.location.href + "?f=share", //...
Download data url file
I'm playing with the idea of making a completely JavaScript-based zip/unzip utility that anyone can access from a browser. They can just drag their zip directly into the browser and it'll let them download all the files within. They can also create new zip files by dragging individual files in.
...
Facebook Android Generate Key Hash
...nload Openssl from: here.
2) Make a openssl folder in C drive
3) Extract Zip files into this openssl folder created in C Drive.
4) Copy the File debug.keystore from .android folder in my case (C:\Users\SYSTEM.android) and paste into JDK bin Folder in my case (C:\Program Files\Java\jdk1.6.0_05\bi...
App Inventor 2 CustomWebView 拓展：高级版Web浏览器，完美浏览现代Web前...
...换 目录 在线 客服 扫码添加客服咨询 我要 分享 扫码分享到朋友圈 顶部 var qrcode = new QRCode("qrcode", { text: window.location.href + "?f=share", ...
How do I detect whether a Python variable is a function?
...n of "function" that is usually not what you need. For example, it rejects zip (technically a class):
>>> type(zip), isinstance(zip, types.FunctionType)
(<class 'type'>, False)
open (built-in functions have a different type):
>>> type(open), isinstance(open, types.Functio...