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data.table vs dplyr: can one do something well the other can't or does poorly?
...j and by together is by design. By keeping related operations together, it allows to easily optimise operations for speed and more importantly memory usage, and also provide some powerful features, all while maintaining the consistency in syntax.
1. Speed
Quite a few benchmarks (though mostly on g...
C++ lambda with captures as a function pointer
... @KerrekSB put the global variables in a namespace and mark them as thread_local, that's the ftw approach I chose for solving something similar.
– Kjell Hedström
Apr 21 '14 at 15:08
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Give all the permissions to a user on a DB
I would like to give an user all the permissions on a database without making it an admin.
The reason why I want to do that is that at the moment DEV and PROD are different DBs on the same cluster so I don't want a user to be able to change production objects but it must be able to change objects on...
Filter dataframe rows if value in column is in a set list of values [duplicate]
... regular expressions.
For example, if we want to return a DataFrame where all of the stock IDs which begin with '600' and then are followed by any three digits:
>>> rpt[rpt['STK_ID'].str.contains(r'^600[0-9]{3}$')] # ^ means start of string
... STK_ID ... ...
Table Naming Dilemma: Singular vs. Plural Names [closed]
...t wanted to add this... Is it possible that "User" (or "Users") is not actually a full description of the data held in the table? Not that you should get too crazy with table names and specificity, but perhaps something like "Widget_Users" (where "Widget" is the name of your application or website) ...
I can't install python-ldap
...n order to compile the Python module. If you're on Ubuntu, the package is called libldap2-dev.
Debian/Ubuntu:
sudo apt-get install libsasl2-dev python-dev libldap2-dev libssl-dev
RedHat/CentOS:
sudo yum install python-devel openldap-devel
...
Encoding as Base64 in Java
... Base64.getEncoder().encodeToString(string.getBytes(StandardCharsets.UTF_8))
Here is a short, self-contained complete example:
import java.nio.charset.StandardCharsets;
import java.util.Base64;
public class Temp {
public static void main(String... args) throws Exception {
final Str...
How to clear Facebook Sharer cache?
...the URL of the page you want to share, and click "debug". It will automatically extract all the info on your meta tags and also clear the cache.
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How to refresh Android listview?
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Call notifyDataSetChanged() on your Adapter object once you've modified the data in that adapter.
Some additional specifics on how/when to call notifyDataSetChanged() can be viewed in this Google I/O video.
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How do I fix “for loop initial declaration used outside C99 mode” GCC error?
...oo.c -o foo
REF: http://cplusplus.syntaxerrors.info/index.php?title='for'_loop_initial_declaration_used_outside_C99_mode
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