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mongodb count num of distinct values per field/key
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115
Here is example of using aggregation API. To complicate the case we're grouping by case-insens...
How can I extract embedded fonts from a PDF as valid font files?
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You have several options. All these methods work on Linux as well as on Windows or Mac OS X. However, be aware that most PDFs do not include to full, complete fontface when they have a font embedded. Mostly they include just the subset of glyphs used ...
可重入函数、不可重入函数及线程安全 - C/C++ - 清泛网 - 专注C/C++及内核技术
... fsync
pipe
sigaction
tcgetpgrp
cfgetospeed
ftruncate
poll
sigaddset
tcsendbreak
cfsetispeed
getegid
posix_trace_event
sigdelset
tcsetattr
cfsetospeed
geteuid
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How does zip(*[iter(s)]*n) work in Python?
... each element is x. *arg unpacks a sequence into arguments for a function call. Therefore you're passing the same iterator 3 times to zip(), and it pulls an item from the iterator each time.
x = iter([1,2,3,4,5,6,7,8,9])
print zip(x, x, x)
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Mongodb Explain for Aggregation framework
...ther manipulation will be in-memory (possibly using temporary files if the allowDiskUse option is set).
Optimizing pipelines
In general, you can optimize aggregation pipelines by:
Starting a pipeline with a $match stage to restrict processing to relevant documents.
Ensuring the initial $match / ...
How to find out if an installed Eclipse is 32 or 64 bit version?
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answered Feb 24 '11 at 10:38
Sam DufelSam Dufel
16.2k33 gold badges4141 silver badges4949 bronze badges
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Why does the order of the loops affect performance when iterating over a 2D array?
... x[1][0] etc...
Meaning that you're hitting them all in order. Now look at the 1st version. You're doing:
x[0][0]
x[1][0]
x[2][0]
x[0][1]
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Disable ALL CAPS menu items in Visual Studio 2013
...l Studio 2013 (as in VS 2012), MS reinforced their design decision to make ALL CAPS MENU ITEMS the default. The methods for reverting the menu style are almost the same methods used for Visual Studio 2012, which has been discussed before.
Update (after Visual Studio 2013 Update 4)
As of Visual Stu...
How to delete a specific line in a file?
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First, open the file and get all your lines from the file. Then reopen the file in write mode and write your lines back, except for the line you want to delete:
with open("yourfile.txt", "r") as f:
lines = f.readlines()
with open("yourfile.txt", "w"...
Create a GUID in Java
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@angel Yes, it is theoretically possible for the UUID.randomUUID method to return a duplicate, but this is not at all a realistic concern. The Oracle/OpenJDK implementation uses a cryptographically-strong random number generator. Given that, and given ...