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How to delete migration files in Rails 3
...le or columns.
Another great reference for migrations is: http://guides.rubyonrails.org/migrations.html
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What is the difference between .map, .every, and .forEach?
...ce is in the return values.
.map() returns a new Array of objects created by taking some action on the original item.
.every() returns a boolean - true if every element in this array satisfies the provided testing function. An important difference with .every() is that the test function may not...
How to get exit code when using Python subprocess communicate method?
...ant documentation section:
Popen.returncode
The child return code, set by poll() and wait() (and indirectly by communicate()).
A None value indicates that the process hasn’t terminated yet.
A negative value -N indicates that the child was terminated by signal N (Unix only).
So you can ...
In bash, how does one clear the current input?
...
Ctrl-A followed by a Ctrl-K also works. The 'killed' text is stored and you can paste it by using Ctrl-Y. These keystrokes in fact come from the read line library: cnswww.cns.cwru.edu/php/chet/readline/rluserman.html .. so you can find them ...
Looping over arrays, printing both index and value
...baz
Explained
printf "%s\n" "${!foo[@]}" will print all keys separated by a newline,
printf "%s\n" "${foo[@]}" will print all values separated by a newline,
paste <(cmd1) <(cmd2) will merge output of cmd1 and cmd2 line by line.
Tunning
This could be tunned by -d switch:
paste -d : <...
What does “to stub” mean in programming?
...le replacement for an Existing Dependency (or collaborator)
in the system. By using a stub, you can test your code without
dealing with the dependency directly.
External Dependency - Existing Dependency:
It is an object in your system that your code
under test interacts with and over which you have...
Share cookie between subdomain and domain
...ie like the second example above from mydomain.com, it would be accessible by subdomain.mydomain.com, and vice versa. This can also be used to allow sub1.mydomain.com and sub2.mydomain.com to share cookies.
See also:
www vs no-www and cookies
cookies test script to try it out
...
JMS Topic vs Queues
... a 1-to-many model of distribution.
The same published message is received by all consuming subscribers. You can also call this the 'broadcast' model. You can think of a topic as the equivalent of a Subject in an Observer design pattern for distributed computing. Some JMS providers efficiently choos...
What's the difference between an exclusive lock and a shared lock?
... readers when the lock chooses who gets the lock next (when it is unlocked by its current owner). This is about policy.
– ArjunShankar
Jun 22 '16 at 12:31
...
Class method differences in Python: bound, unbound and static
... instance properties.
3
>>> Class.c # a.c above was passed by value and not by reference.
2
>>> a.c
2
>>> a.c = 5 # The connection between the instance
>>> Class.c # and its class is weak as seen here.
2
>>> Class.class_method()
3
>...