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Pandas every nth row
...simpler solution to the accepted answer that involves directly invoking df.__getitem__.
df = pd.DataFrame('x', index=range(5), columns=list('abc'))
df
a b c
0 x x x
1 x x x
2 x x x
3 x x x
4 x x x
For example, to get every 2 rows, you can do
df[::2]
a b c
0 x x x
...
Get the Query Executed in Laravel 3/4
...:getQueryLog() to get all ran queries.
$queries = DB::getQueryLog();
$last_query = end($queries);
Or you can download a profiler package. I'd recommend barryvdh/laravel-debugbar, which is pretty neat. You can read for instructions on how to install in their repository.
Note for Laravel 5 users: ...
Number of processors/cores in command line
...
The most simplest tool comes with glibc and is called getconf:
$ getconf _NPROCESSORS_ONLN
4
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Is “double hashing” a password less secure than just hashing it once?
...lled "key strengthening" or "key stretching". See en.wikipedia.org/wiki/Key_stretching
– user41871
Dec 7 '08 at 22:40
17
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Changing selection in a select with the Chosen plugin
...-selected", function() {
var locID = jQuery(this).attr('class').split('__').pop();
// I have a class name: class="result-selected locvalue__209"
var arrayCurrent = jQuery('#searchlocation').val();
var index = arrayCurrent.indexOf(locID);
if (index > -1) {
arrayCurrent....
What is the strict aliasing rule?
...sg) onto a buffer of the word size of your system (like a pointer to uint32_ts or uint16_ts). When you overlay a struct onto such a buffer, or a buffer onto such a struct through pointer casting you can easily violate strict aliasing rules.
So in this kind of setup, if I want to send a message to so...
How to correctly save instance state of Fragments in back stack?
...tManager()
.beginTransaction()
.add(R.id.my_container, myFragment, MY_FRAGMENT_TAG)
.commit();
} else {
myFragment = (MyFragment) getSupportFragmentManager()
.findFragmentByTag(MY_FRAGMENT_TAG);
}
...
}
Note however th...
What does the “===” operator do in Ruby? [duplicate]
...ux
flurb
else
blarf
end
gets translated to something (roughly) like
_temp = foo
if bar === _temp
baz
elsif quux === _temp
flurb
else
blarf
end
Note that if you want to search for this operator, it is usually called the triple equals operator or threequals operator or case equality op...
Python Pandas merge only certain columns
...
Hmmm ... I tried using this to merge column 'Unique_External_Users' from df2 to df1 but got an error ... "None of [Index(['U', 'n', 'i', 'q', 'u', 'e', '', 'E', 'x', 't', 'e', 'r', 'n', 'a',\n 'l', '', 'U', 's', 'e', 'r', 's'],\n dtype='object')] are in the [column...
Determine Whether Two Date Ranges Overlap
...
Proof:
Let ConditionA Mean that DateRange A Completely After DateRange B
_ |---- DateRange A ------|
|---Date Range B -----| _
(True if StartA > EndB)
Let ConditionB Mean that DateRange A is Completely Before DateRange B
|---- DateRange A ...