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How can I implement a tree in Python?
...cation
pre-order tree iteration
post-order tree iteration
resolve relative and absolute node paths
walking from one node to an other.
tree rendering (see example above)
node attach/detach hookups
share
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What is a segmentation fault?
What is a segmentation fault? Is it different in C and C++? How are segmentation faults and dangling pointers related?
14 A...
DatabaseError: current transaction is aborted, commands ignored until end of transaction block?
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This is what postgres does when a query produces an error and you try to run another query without first rolling back the transaction. (You might think of it as a safety feature, to keep you from corrupting your data.)
To fix this, you'll want to figure out where in the code that ...
How do you express binary literals in Python?
... answered Aug 16 '08 at 12:35
Andreas ThomasAndreas Thomas
3,81033 gold badges2020 silver badges1515 bronze badges
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Postgresql 9.2 pg_dump version mismatch
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I encountered this while using Heroku on Ubuntu, and here's how I fixed it:
Add the PostgreSQL apt repository as described at "Linux downloads (Ubuntu)
". (There are similar pages for other operating systems.)
Upgrade to the latest version (9.3 for me) with:
sudo apt-ge...
How to find the installed pandas version
I am having trouble with some of pandas functionalities. How do I check what is my installation version?
6 Answers
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Storing custom objects in an NSMutableArray in NSUserDefaults
...ed to grab the array:
NSUserDefaults *currentDefaults = [NSUserDefaults standardUserDefaults];
NSData *dataRepresentingSavedArray = [currentDefaults objectForKey:@"savedArray"];
if (dataRepresentingSavedArray != nil)
{
NSArray *oldSavedArray = [NSKeyedUnarchiver unarchiveObjectWithData:dataRepr...
How set background drawable programmatically in Android
...rrect.
Another way to achieve it is to use the following:
final int sdk = android.os.Build.VERSION.SDK_INT;
if(sdk < android.os.Build.VERSION_CODES.JELLY_BEAN) {
layout.setBackgroundDrawable(ContextCompat.getDrawable(context, R.drawable.ready) );
} else {
layout.setBackground(ContextComp...
Upload file to FTP using C#
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The existing answers are valid, but why re-invent the wheel and bother with lower level WebRequest types while WebClient already implements FTP uploading neatly:
using (var client = new WebClient())
{
client.Credentials = new NetworkCredential(ftpUsername, ftpPassword);
clien...
Run a PostgreSQL .sql file using command line arguments
I have some .sql files with thousands of INSERT statements in them and need to run these inserts on my PostgreSQL database in order to add them to a table. The files are that large that it is impossible to open them and copy the INSERT statements into an editor window and run them there. I found on ...