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Python loop that also accesses previous and next values
How can I iterate over a list of objects, accessing the previous, current, and next items? Like this C/C++ code, in Python?
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MySQL error: key specification without a key length
...r BLOB types such as TINYBLOB, MEDIUMBLOB, LONGBLOB, TINYTEXT, MEDIUMTEXT, and LONGTEXT that you try to make a primary key or index. With full BLOB or TEXT without the length value, MySQL is unable to guarantee the uniqueness of the column as it’s of variable and dynamic size. So, when using BLOB ...
Clean ways to write multiple 'for' loops
.../ ...
}
(or just:
for ( auto& elem: m ) {
}
if you have C++11.)
And if you need the three indexes during such iterations, it's
possible to create an iterator which exposes them:
class Matrix3D
{
// ...
class iterator : private std::vector<int>::iterator
{
Matri...
Global and local variables in R
I am a newbie for R, and I am quite confused with the usage of local and global variables in R.
3 Answers
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SQL multiple column ordering
I am trying to sort by multiple columns in SQL, and in different directions. column1 would be sorted descending, and column2 ascending.
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MySql Table Insert if not exist otherwise update
... description bugs.mysql.com/bug.php?id=58637
– broadband
Sep 2 '14 at 13:28
1
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Simple way to copy or clone a DataRow?
... to make a clone of a DataRow. Kind of like taking a snapshot of that Row and saving it. The values of original Row are then free to change but we still have another saved copy which doesn't change. Is this the correct way to do it?
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Position Relative vs Absolute?
What is the difference between position: relative and position: absolute in CSS? And when should you use them?
10 Answe...
Why is '+' not understood by Python sets?
...'t have an implementation for the + operator.
You can use | for set union and & for set intersection.
Sets do implement - as set difference. You can also use ^ for symmetric set difference (i.e., it will return a new set with only the objects that appear in one set but do not appear in both se...
Are arrays in PHP copied as value or as reference to new variables, and when passed to functions?
...e
copying. Use the reference operator to
copy an array by reference.
And the given example :
<?php
$arr1 = array(2, 3);
$arr2 = $arr1;
$arr2[] = 4; // $arr2 is changed,
// $arr1 is still array(2, 3)
$arr3 = &$arr1;
$arr3[] = 4; // now $arr1 and $arr3 are the same
?>
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