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How to reshape data from long to wide format
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The reshape comments and similar argument names aren't all that helpful. However, I have found that for long to wide, you need to provide data = your data.frame, idvar = the variable that identifies your groups, v.names = the variables that will become multiple columns in wide f...
Laravel migration: unique key is too long, even if specified
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Specify a smaller length for your e-mail:
$table->string('email', 250);
Which is the default, actually:
$table->string('email');
And you should be good.
For Laravel 5.4 you can find a solution in this Laravel 5.4: Specified ...
How do I determine the target architecture of static library (.a) on Mac OS X?
...cutable ppc
Example with archive:
logan:/Users/logan% file /usr/lib/libMallocDebug.a
/usr/lib/libMallocDebug.a: Mach-O universal binary with 2 architectures
/usr/lib/libMallocDebug.a (for architecture i386): current ar archive random library
/usr/lib/libMallocDebug.a (for architecture ppc): ...
What Makes a Good Unit Test? [closed]
...ng lots of automated tests and that you also have run into some common pitfalls when unit testing.
18 Answers
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Retrieve only the queried element in an object array in MongoDB collection
...r to filter an array during projection, which has the benefit of including all matches, instead of just the first one.
db.test.aggregate([
// Get just the docs that contain a shapes element where color is 'red'
{$match: {'shapes.color': 'red'}},
{$project: {
shapes: {$filter: {
...
Is it better in C++ to pass by value or pass by constant reference?
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It used to be generally recommended best practice1 to use pass by const ref for all types, except for builtin types (char, int, double, etc.), for iterators and for function objects (lambdas, classes deriving from std::*_function).
This was es...
How to deal with INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES without uninstall?
I tried to reinstall an apk
16 Answers
16
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Drop all tables whose names begin with a certain string
How can I drop all tables whose names begin with a given string?
14 Answers
14
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How to remove constraints from my MySQL table?
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Postgres, MSSQL, and Oracle all have alter table .. drop constraint. MySQL is the odd one out, it seems.
– Jared Beck
Mar 23 '15 at 23:48
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Where does gcc look for C and C++ header files?
...stem header.
If you run gcc in verbose mode on such a source, it will list all the system include locations as it looks for the bogus header.
$ echo "#include <bogus.h>" > t.c; gcc -v t.c; rm t.c
[..]
#include "..." search starts here:
#include <...> search starts here:
/usr/local...