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How to implement the activity stream in a social network
...stream for any user and then grab the related data from the db as needed. Fall back to querying the db by time if the user needs to browse far back in time (if you even offer this)
I use a plain old MySQL table for dealing with about 15 million activities.
It looks something like this:
id ...
What does $_ mean in PowerShell?
...
This is the variable for the current value in the pipe line, which is called $PSItem in Powershell 3 and newer.
1,2,3 | %{ write-host $_ }
or
1,2,3 | %{ write-host $PSItem }
For example in the above code the %{} block is called for every value in the array. The $_ or $PSItem variable ...
What are the applications of binary trees?
...ningless - they are not a data structure, but a family of data structures, all with different performance characteristics. While it is true that unbalanced binary trees perform much worse than self-balancing binary trees for searching, there are many binary trees (such as binary tries) for which "b...
How do I get the full path to a Perl script that is executing?
...me of the script during execution. I discovered that depending on how you call the script $0 varies and sometimes contains the fullpath+filename and sometimes just filename . Because the working directory can vary as well I can't think of a way to reliably get the fullpath+filename of the scr...
How do CDI and EJB compare? interact?
...s, different implementations or algorithms (so you don't need EJB there at all).
EJB: you do understand, and probably you are confused by @EJB annotation - it allows you to inject implementation into your service or whatever. The main idea is that class, where you inject, should be managed by EJB co...
JavaScript Regular Expression Email Validation [duplicate]
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If you define your regular expression as a string then all backslashes need to be escaped, so instead of '\w' you should have '\\w'.
Alternatively, define it as a regular expression:
var pattern = /^\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,3}$/;
BTW, please don't validate email address...
Forced naming of parameters in Python
...(10, forcenamed=20)
10 20
>>> foo(10, 20)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: foo() takes exactly 1 positional argument (2 given)
This can also be combined with **kwargs:
def foo(pos, *, forcenamed, **kwargs):
...
What do (lambda) function closures capture?
...the name and scope of the variable, not the object it's pointing to. Since all the functions in your example are created in the same scope and use the same variable name, they always refer to the same variable.
EDIT: Regarding your other question of how to overcome this, there are two ways that com...
Printf width specifier to maintain precision of floating-point value
...ier which can be applied to a floating point specifier that would automatically format the output to the necessary number of significant digits such that when scanning the string back in, the original floating point value is acquired?
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Can modules have properties the same way that objects can?
...s? When I put this code in one file x.py and import it from another, then calling x.y results in AttributeError: 'NoneType' object has no attribute 'c', since _M somehow has value None...
– Stephan202
May 19 '09 at 1:35
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