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Rails 4 multiple image or file upload using carrierwave
...ke a look at CarrierWave's documentation, this is actually very easy now.
https://github.com/carrierwaveuploader/carrierwave/blob/master/README.md#multiple-file-uploads
I will use Product as the model I want to add the pictures, as an example.
Get the master branch Carrierwave and add it to your...
ERROR: Error 1005: Can't create table (errno: 121)
...un an ALTER TABLE with certain constraint names.
According to the docs at http://dev.mysql.com/doc/refman/5.7/en/innodb-troubleshooting-datadict.html , you can search for these orphan tables with:
SELECT * FROM INFORMATION_SCHEMA.INNODB_SYS_TABLES WHERE NAME LIKE '%#sql%';
The version I was work...
How to implement a queue with three stacks?
...iginal question
DETAILS
There are two implementations behind this link: http://www.eecs.usma.edu/webs/people/okasaki/jfp95/index.html
One of them is O(1) with three stacks BUT it uses lazy execution, which in practice creates extra intermediate data structures (closures).
Another of them is O(1...
ipython reads wrong python version
...
extremely relevant: http://conda.pydata.org/docs/troubleshooting.html#shell-command-location.
td;lr problems are encountered because of shell 'hashing' and path variables.
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How do you get a Golang program to print the line number of the error it just called?
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If you need exactly a stack trace, take a look at https://github.com/ztrue/tracerr
I created this package in order to have both stack trace and source fragments to be able to debug faster and log errors with much more details.
Here is a code example:
package main
import ...
Struct like objects in Java
...ct), then it's appropriate to make the class's instance variables public.
http://www.oracle.com/technetwork/java/javase/documentation/codeconventions-137265.html#177
http://en.wikipedia.org/wiki/Plain_old_data_structure
http://docs.oracle.com/javase/1.3/docs/guide/collections/designfaq.html#28
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Logging uncaught exceptions in Python
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The method sys.excepthook will be invoked if an exception is uncaught: http://docs.python.org/library/sys.html#sys.excepthook
When an exception is raised and uncaught, the interpreter calls sys.excepthook with three arguments, the exception class, exception instance, and a traceback object. ...
What is the difference between linear regression and logistic regression?
...an 0, or even bigger than
1, logistic regression was introduced.
Source: http://gerardnico.com/wiki/data_mining/simple_logistic_regression
Outcome
In linear regression, the outcome (dependent variable) is continuous.
It can have any one of an infinite number of possible values.
In logistic re...
Add custom messages in assert?
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BOOST_ASSERT_MSG(expre, msg)
http://www.boost.org/doc/libs/1_51_0/libs/utility/assert.html
You could either use that directly or copy Boost's code. Also note Boost assert is header only, so you could just grab that single file if you didn't want to inst...
Why compile Python code?
...PHP and others.
Heres an interesting blog post explaining the differences http://julipedia.blogspot.com/2004/07/compiled-vs-interpreted-languages.html
And here's an entry that explains the Python compile process http://effbot.org/zone/python-compile.htm
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