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Run a single migration file
...f the ruby file:
rails console
>> require "db/migrate/20090408054532_add_foos.rb"
>> AddFoos.up
Note: newer versions of rails may require AddFoos.new.up rather than AddFoos.up.
An alternative way (without IRB) which relies on the fact that require returns an array of class names:
sc...
AWS S3 copy files and folders between two buckets
...
A simplified example using the aws-sdk gem:
AWS.config(:access_key_id => '...', :secret_access_key => '...')
s3 = AWS::S3.new
s3.buckets['bucket-name'].objects['source-key'].copy_to('target-key')
If you want to perform the copy between different buckets, then specify the target ...
Create a “with” block on several context managers? [duplicate]
...nd 3.1 and above, you can write:
with A() as X, B() as Y, C() as Z:
do_something()
This is normally the best method to use, but if you have an unknown-length list of context managers you'll need one of the below methods.
In Python 3.3, you can enter an unknown-length list of context manage...
Swift: #warning equivalent
...mple all at the same time.
// Description of what you need to fix
var FIX_ME__????????????: AnyObject
Throws a warning that 'FIX_ME__????????????' was never used.
You can add emoticons to the variable name if you like... I often use ???? and ????, for something that really needs fixing I'd eve...
Add Variables to Tuple
...
>>> from dis import dis
>>> dis(f)
2 0 LOAD_CONST 1 (('foo', 'bar'))
2 STORE_FAST 0 (tuple1)
3 4 LOAD_FAST 0 (tuple1)
6 LOAD_CONST 3 (('baz',))
8 BUILD_TUPL...
Hidden features of Perl?
...
Cool! !!$undef_var doesn't create a warning.
– Axeman
Oct 2 '08 at 20:40
4
...
clang error: unknown argument: '-mno-fused-madd' (python package installation failure)
...s/2.7/include/python2.7 -fno-strict-aliasing -fno-common -dynamic -arch x86_64 -arch i386 -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -mno-fused-madd -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DT...
What do linkers do?
..., let's study a NASM x86-64 ELF Linux hello world:
section .data
hello_world db "Hello world!", 10
section .text
global _start
_start:
; sys_write
mov rax, 1
mov rdi, 1
mov rsi, hello_world
mov rdx, 13
syscall
; sys_exit
...
Leading zeros for Int in Swift
...wn below in order to solve your problem.
#1. Using String's init(format:_:) initializer
Foundation provides Swift String a init(format:_:) initializer. init(format:_:) has the following declaration:
init(format: String, _ arguments: CVarArg...)
Returns a String object initialized by using ...
Are duplicate keys allowed in the definition of binary search trees?
...about them. As just a starter, take a look here: en.wikipedia.org/wiki/List_of_data_structures#Trees
– Andrew
Sep 16 at 0:52
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