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Why do you need to create a cursor when querying a sqlite database?
I'm completely new to Python's sqlite3 module (and SQL in general for that matter), and this just completely stumps me. The abundant lack of descriptions of cursor objects (rather, their necessity) also seems odd.
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Merging without whitespace conflicts
...'ve got a problem where I've got a large commit which changes about a thousand lines of code, removing whitespace from the end of lines and removing spaces before tabs.
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Copying a HashMap in Java
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Maybe i'm not understanding this but I don't need a copy of the map. I need a copy of the class that holds the map. ? There for myObjectListB has to be a class derived from MyojbectsList not a hashmap.
– user691305
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Xml Namespace breaking my xpath! [duplicate]
... there my xPath finds nothing
If you cannot register a namespace binding and cannot use (assuming the registered prefix is "x"):
/x:List/x:Fields/x:Field
then there is another way:
/*[name()='List']/*[name()='Fields']/*[name()='Field']
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“Large data” work flows using pandas
...d to puzzle out an answer to this question for many months while learning pandas. I use SAS for my day-to-day work and it is great for it's out-of-core support. However, SAS is horrible as a piece of software for numerous other reasons.
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Renaming a virtualenv folder without breaking it
I've created folder and initialized a virtualenv instance in it.
10 Answers
10
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Convert SVG to PNG in Python
...ry.
I made a minimalist "hello world" that renders SVG to a cairo
surface and writes it to disk:
import cairo
import rsvg
img = cairo.ImageSurface(cairo.FORMAT_ARGB32, 640,480)
ctx = cairo.Context(img)
## handle = rsvg.Handle(<svg filename>)
# or, for in memory SVG data:
handle= rsvg.Hand...
Rails 2.3-style plugins and deprecation warnings running task in Heroku
I'm upgrading to Rails 3.2, and running rake db:migrate gives me several errors of the form:
8 Answers
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Read file line by line using ifstream in C++
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#include <fstream>
std::ifstream infile("thefile.txt");
The two standard methods are:
Assume that every line consists of two numbers and read token by token:
int a, b;
while (infile >> a >> b)
{
// process pair (a,b)
}
Line-based parsing, using string streams:
#include ...
What is a memory fence?
...are concept. In higher level languages we are used to dealing with mutexes and semaphores - these may well be implemented using memory fences at the low level and explicit use of memory barriers are not necessary. Use of memory barriers requires a careful study of the hardware architecture and more ...