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How do I delete a fixed number of rows with sorting in PostgreSQL?
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Postgres docs recommend to use array instead of IN and subquery. This should work much faster
DELETE FROM logtable
WHERE id = any (array(SELECT id FROM logtable ORDER BY timestamp LIMIT 10));
This and some other tricks can be found here
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Multiple linear regression in Python
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The reg_m function is unnecessarily complicated. x = np.array(x).T, x = sm.add_constant(x) and results = sm.OLS(endog=y, exog=x).fit() is enough.
– cd98
Nov 14 '14 at 23:26
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How to use Jackson to deserialise an array of objects
...ata binding documentation indicates that Jackson supports deserialising "Arrays of all supported types" but I can't figure out the exact syntax for this.
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Are trailing commas in arrays and objects part of the spec?
...as just:
ObjectLiteral :
{ }
{ PropertyNameAndValueList }
For arrays literals (Section 11.1.4) it is even more interesting (Update: this already existed in ES3):
ArrayLiteral :
[ Elisionopt ]
[ ElementList ]
[ ElementList , Elision_opt ]
(where Elision_opt is Elisionopt, ...
How do I create JavaScript array (JSON format) dynamically?
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Our array of objects
var someData = [
{firstName: "Max", lastName: "Mustermann", age: 40},
{firstName: "Hagbard", lastName: "Celine", age: 44},
{firstName: "Karl", lastName: "Koch", age: 42},
];
with for...in
var em...
Creating dataframe from a dictionary where entries have different lengths
Say I have a dictionary with 10 key-value pairs. Each entry holds a numpy array. However, the length of the array is not the same for all of them.
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How do I set a variable to the output of a command in Bash?
...d y for port number:
{
read -u $list -a head # read header in array `head`
varnames=(${head[@]//[K1% -]}) # drop illegal chars for variable names
while read -u $list ${varnames[@],,} ;do
((pct=available*100/(available+used),pct<10)) &&
printf "WARN...
How can I correctly prefix a word with “a” and “an”?
...one in PHP by Jaimie Sirovich :
function aOrAn($next_word)
{
$_an = array('hour', 'honest', 'heir', 'heirloom');
$_a = array('use', 'useless', 'user');
$_vowels = array('a','e','i','o','u');
$_endings = array('ly', 'ness', 'less', 'lessly', 'ing', 'ally', 'ially');
$_endi...
How to make my custom type to work with “range-based for loops”?
...ethod, or ADL-only lookup of free function begin/end, or magic for C-style array support. Note that std::begin is not called unless range_expression returns an object of type in namespace std or dependent on same.
In c++17 the range-for expression has been updated
{
auto && __range = ran...
Java: Get last element after split
...e String split method and I want to have the last element.
The size of the Array can change.
12 Answers
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