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Please explain some of Paul Graham's points on Lisp
...gt; STRING
2) A symbol type. Symbols differ from strings in that you can test equality by comparing a pointer.
A symbol is a data object with a name. Usually the name can be used to find the object:
|This is a Symbol|
this-is-also-a-symbol
(find-symbol "SIN") -> SIN
Since symbols are re...
Is it possible to set the equivalent of a src attribute of an img tag in CSS?
.../SZ8Cm.jpg");
}
</style>
<img class="MyClass123"/>
Tested and working:
Chrome 14.0.835.163
Safari 4.0.5
Opera 10.6
Tested and Not working:
FireFox 40.0.2 (observing Developer Network Tools, you can see that the URL loads, but the image is not displayed)
Internet Expl...
No ConcurrentList in .Net 4.0?
...This was the goal of my ConcurrentList<T> implementation. But when I tested its performance in multithreaded scenarios, I found that simply synchronizing adds to a List<T> was faster. Basically, adding to a List<T> is lightning fast already; the complexity of the computational step...
Calling clojure from java
... This example used the Clojure-1.1.0 jar.
Update: This answer has been re-tested using the following tools:
Clojure 1.5.1
Leiningen 2.1.3
JDK 1.7.0 Update 25
The Clojure Part
First create a project and associated directory structure using Leiningen:
C:\projects>lein new com.domain.tiny
N...
Which parts of Real World Haskell are now obsolete or considered bad practice?
...een replaced with more general Foldable t => t a variants.
Chapter 11. Testing and quality assurance
Since Haskell-platform 2010 or late 2008.
Although this is mentioned in a footnote, the QuickCheck library has changed in many ways from version 1 to version 2. For example, generate now uses G...
Best practices for using Markers in SLF4J/Logback
...ng, and Markers are for filtering. These activities are carried out during testing and in production. As such, you need to decide which dimensions you expect may be useful to slice the log data by, and which cases it might be useful to filter it against, when testing/production comes around. Each di...
How can I plot with 2 different y-axes?
...apted from an R mailing list post by Robert W. Baer):
## set up some fake test data
time <- seq(0,72,12)
betagal.abs <- c(0.05,0.18,0.25,0.31,0.32,0.34,0.35)
cell.density <- c(0,1000,2000,3000,4000,5000,6000)
## add extra space to right margin of plot within frame
par(mar=c(5, 4, 4, 6) + ...
Is it better to call ToList() or ToArray() in LINQ queries?
...I wanted to benchmark it to be sure, so I did - and it is, insignificant.
Testing with List<T> source:
ToArray time: 1934 ms (0.01934 ms/call), memory used: 4021 bytes/array
ToList time: 1902 ms (0.01902 ms/call), memory used: 4045 bytes/List
Testing with array source:
ToArray time: 1957 ms...
How to upload a file in Django? [closed]
...s are created::
uploader/
__init__.py
admin.py
app.py
models.py
tests.py
views.py
migrations/
__init__.py
3. Update settings.py
On sample/settings.py add 'uploader' to INSTALLED_APPS and add MEDIA_ROOT and MEDIA_URL, ie::
INSTALLED_APPS = [
'uploader',
...<other app...
What's the difference between EscapeUriString and EscapeDataString?
...
... did some testing looks like I want EscapeDataString for a URI parameter. I tested with the string "I heart C++" and EscapeUriString did not encode the "+" characters, it just left them as is, EscapeDataString correctly converted them...