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Migration: Cannot add foreign key constraint
...signed();
$table->string('priority_name');
$table->smallInteger('rank');
$table->text('class');
$table->timestamps('timecreated');
});
Schema::table('priorities', function($table) {
$table->foreign('user_id')->references('id')->on('...
C++ equivalent of java's instanceof
...nceof) you'd better ask yourself whether it's a necessary thing. It's generally a sign of poor design.
Typical workarounds is putting the special behaviour for the class you are checking for into a virtual function on the base class or perhaps introducing something like a visitor where you can int...
What is the difference between String.Empty and “” (empty string)?
...ich makes string.Empty more efficient.
In version 2.0 and later of .NET, all occurrences of "" refer to the same string literal, which means "" is equivalent to .Empty, but still not as fast as .Length == 0.
.Length == 0 is the fastest option, but .Empty makes for slightly cleaner code.
See the ...
Visual Studio support for new C / C++ standards?
I keep reading about C99 and C++11 and all these totally sweet things that are getting added to the language standard that might be nice to use someday. However, we currently languish in the land of writing C++ in Visual Studio.
...
How to set Python's default version to 3.x on OS X?
...n use command python, which will leaving the alias untouched, and works in all shells.
If you launch interpreters more often (I do), you can always create more aliases to add as well, i.e.:
alias 2='python2'
alias 3='python3'
Tip: For scripts, instead of using a shebang like:
#!/usr/bin/env p...
Learning Python from Ruby; Differences and Similarities
...
[x*x for x in values if x > 15]
to get a new list of the squares of all values greater than 15. In Ruby, you'd have to write the following:
values.select {|v| v > 15}.map {|v| v * v}
The Ruby code doesn't feel as compact. It's also not as efficient since it first converts the values a...
Django: How to manage development and production settings?
...s you define environment variables in an "environment" (.env) file.
Finally, note that you can take advantage of the PYTHONPATH variable to store the settings in a completely different location (e.g. on a production server, storing them in /etc/). This allows for separating configuration from ap...
boost::flat_map and its performance compared to map and unordered_map
...e, because your cache will not be warm, and your operation will likely be called just once. Therefore you need to benchmark using RDTSC, and time stuff calling them once only.
Intel has made a paper describing how to use RDTSC (using a cpuid instruction to flush the pipeline, and calling it at least...
How do you read a file into a list in Python? [duplicate]
...each line might have. When the with ends, the file will be closed automatically for you. This is true even if an exception is raised inside of it.
2. use of list comprehension
This could be considered inefficient as the file descriptor might not be closed immediately. Could be a potential issue wh...
What is the difference between char array and char pointer in C?
...char* and char[] are different types, but it's not immediately apparent in all cases. This is because arrays decay into pointers, meaning that if an expression of type char[] is provided where one of type char* is expected, the compiler automatically converts the array into a pointer to its first el...