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How to reshape data from long to wide format
...ear "value" column. Try dat <- data.frame(id=c(1,1,2,2),blah=c(8,4,7,6),index=c(1,2,1,2)); dcast(dat, id ~ index); cast(dat, id ~ index) and you will not get what you expect. You need to explicitly note the value/value.var - cast(dat, id ~ index, value="blah") and dcast(dat, id ~ index, value.var...
Checking a Python module version at runtime
...to suggest that you don't check at run time (don't know if that's a hard requirement or not). For the python stuff I write that has external dependencies (3rd party libraries), I write a script that users can run to check their python install to see if the appropriate versions of modules are instal...
Javascript Array.sort implementation?
...7 - 891
var QuickSort = function QuickSort(a, from, to) {
var third_index = 0;
while (true) {
// Insertion sort is faster for short arrays.
if (to - from <= 10) {
InsertionSort(a, from, to);
return;
}
if (to - from > 1000) {
third_inde...
Is there a MySQL option/feature to track history of changes to records?
... the data table.
To do this sequencing behavior a two column (composite) index is created on the primary key column and revision column. Note that you can only do sequencing in this fashion if the engine used by the history table is MyISAM (See 'MyISAM Notes' on this page)
The history table is fa...
Practical uses of git reset --soft?
...D, and generally the branch ref.
Question: what about the working tree and index?
When employed with --soft, moves HEAD, most often updating the branch ref, and only the HEAD.
This differ from commit --amend as:
it doesn't create a new commit.
it can actually move HEAD to any commit (as commit --a...
How long does it take for GitHub page to show changes after changing index.html
...824%2fhow-long-does-it-take-for-github-page-to-show-changes-after-changing-index-html%23new-answer', 'question_page');
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How to change identity column values programmatically?
...oning, apparently). Note that the table has to match pretty-much exactly (indexes, FKs, etc)
– Mark Sowul
Sep 9 '14 at 14:22
...
How many Activities vs Fragments?
...ole new activity in which it is displayed.
*/
void showDetails(int index)
{
mCurCheckPosition = index;
if (mDualPane)
{
// We can display everything in-place with fragments, so update
// the list to highlight the selected item and show the...
What is a rune?
...akes 1 ~ 3 bytes, while each rune takes 4 bytes
For string, both len() and index are based on bytes.
For []rune, both len() and index are based on rune (or int32).
Relationships - string & []rune:
When you convert from string to []rune, each utf-8 char in that string becomes a rune.
Similarl...
What's the correct way to convert bytes to a hex string in Python 3?
...ht but something that was argued over: bugs.python.org/issue3532#msg70950. Q: Would it hurt to have the tohex method of the bytes object to perform this task as well? A: IMO, yes, it would. It complicates the code, and draws the focus away from the proper approach to data conversion (namely, functio...