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When to use os.name, sys.platform, or platform.system?
...specific modules are available (e.g. posix, nt, ...)
platform.system() actually runs uname and potentially several other functions to determine the system type at run time.
My suggestion:
Use os.name to check whether it's a posix-compliant system.
Use sys.platform to check whether it's a linux,...
What is the difference between `after_create` and `after_save` and when to use which?
... readers should note that, according to the docs, ActiveRecord's update_all does not invoke any callbacks, including after_*
– user2426679
Jan 10 at 19:34
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What are the mathematical/computational principles behind this game?
My kids have this fun game called Spot It! The game constraints (as best I can describe) are:
9 Answers
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Easiest way to check for an index or a key in an array?
... associative array)
[ ${array[key]+abc} ] && echo "exists"
Basically what ${array[key]+abc} does is
if array[key] is set, return abc
if array[key] is not set, return nothing
References:
See Parameter Expansion in Bash manual and the little note
if the colon is omitted, the ope...
How do you increase the max number of concurrent connections in Apache?
...ts 200
MinSpareThreads 25
MaxSpareThreads 75
ThreadsPerChild 25
First of all, whenever an apache is started, it will start 2 child processes which is determined by StartServers parameter. Then each process will start 25 threads determined by ThreadsPerChild parameter so this means 2 process can se...
Specifying and saving a figure with exact size in pixels
...):
plt.figure(figsize=(800/my_dpi, 800/my_dpi), dpi=my_dpi)
So you basically just divide the dimensions in inches by your DPI.
If you want to save a figure of a specific size, then it is a different matter. Screen DPIs are not so important anymore (unless you ask for a figure that won't fit in ...
Given final block not properly padded
...here:
http://www.rsa.com/products/bsafe/documentation/cryptoj35html/doc/dev_guide/group_CJ_SYM__PAD.html
(I assume you have the issue when you try to encrypt)
You can choose your padding schema when you instantiate the Cipher object. Supported values depend on the security provider you are using. ...
Join strings with a delimiter only if strings are not null or empty
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.filter(Boolean) (which is the same as .filter(x => x)) removes all "falsy" values (nulls, undefineds, empty strings etc). If your definition of "empty" is different, then you'll have to provide it, for example:
[...].filter(x => typeof x === 'string' && x.length > 0)
wi...
How do I add a tool tip to a span element?
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Hi, Can someone clarify if this is standard in some/all HTML flavor?
– Jonathan dos Santos
Mar 20 '13 at 13:34
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In c++ what does a tilde “~” before a function name signify?
... memory, etc. etc.
Here's a description from ibm.com:
Destructors are usually used to deallocate memory and do other cleanup for a class object and its class members when the object is destroyed. A destructor is called for a class object when that object passes out of scope or is explicitly delete...