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The differences between .build, .create, and .create! and when should they be used?
...ch of the if statement will always be executed even if the object fails validations and is not saved.
If you use create with branching logic you are at risk of silent failures which is not the case if you use new + save.
create! doesn't suffer from the same issue as it raises and exception if the ...
ASP.NET “special” tags
...
The official name is "server-side scripting delimiters" or "ASP.NET inline expressions". Visual Studio 2008 syntax highlighting settings dialog calls these "HTML Server-Side Script". Microsoft guys call them "code nuggets" in their blogs.
<%@ %> i...
Cost of len() function
...n implementation of the Python language. Here's a link to a table that provides the algorithmic complexity of many different functions in CPython:
TimeComplexity Python Wiki Page
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MySQL error: key specification without a key length
...number of rows. Here is one example for test table:
+-----+-----------+
| id | value |
+-----+-----------+
| 1 | abc |
| 2 | abd |
| 3 | adg |
+-----+-----------+
If we index only the first character (N=1), then index table will look like the following table:
+------...
Asynchronous shell commands
...
$ myscript &
Note that this is different from putting the & inside your script, which probably won't do what you want.
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How do I provide JVM arguments to VisualVM?
...t have enough memory to take a snapshot, and to use the -Xmx switch to provide more memory to Netbeans. The problem is, I'm running VisualVM outside of Netbeans, so how can I provide JVM arguments to jvisualvm.exe?
...
d3 axis labeling
... .attr("class", "x label")
.attr("text-anchor", "end")
.attr("x", width)
.attr("y", height - 6)
.text("income per capita, inflation-adjusted (dollars)");
And the y-axis label like this:
svg.append("text")
.attr("class", "y label")
.attr("text-anchor", "end")
.attr("y",...
Editing Javascript using Chrome Developer Tools
... I have read about 30 accounts of how to do this as well as watched a few videos. The fact is, when I go to the sources tab and open the file I want to edit, I can't do anything to it. Is there some step I am missing?
...
Do git tags get pushed as well?
...ing others to use git push --tags as it can be very very difficult to get rid of bad tags when your co-workers are trained to push all tags, as people continue to push the old bad tags they have locally every time they want to push a new tag. Because of this, I will only every advise someone to use ...
When is JavaScript's eval() not evil?
...s look at the dangers in the use of eval(). There are probably many small hidden dangers just like everything else, but the two big risks - the reason why eval() is considered evil - are performance and code injection.
Performance - eval() runs the interpreter/compiler. If your code is compiled, t...