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What are the applications of binary trees?
...gnatures in which a hash needs to be verified, but the whole file is not available.
Heaps - Used in implementing efficient priority-queues, which in turn are used for scheduling processes in many operating systems, Quality-of-Service in routers, and A* (path-finding algorithm used in AI applications...
How to add line break for UILabel?
...ize:lineBreakMode:
Reference, Replacement for deprecated sizeWithFont: in iOS 7?
CGSize labelSize = [label.text sizeWithAttributes:@{NSFontAttributeName:label.font}];
label.frame = CGRectMake(
label.frame.origin.x, label.frame.origin.y,
label.frame.size.width, labelSize.height);
...
How do I use shell variables in an awk script?
... v1.5
Using -v (The best way, most portable)
Use the -v option: (P.S. use a space after -v or it will be less portable. E.g., awk -v var= not awk -vvar=)
variable="line one\nline two"
awk -v var="$variable" 'BEGIN {print var}'
line one
line two
This should be compatible with most a...
How to hide the “back” button in UINavigationController?
Do you know how to hide the 'back' button in a UINavigationController?
Also, how to show it back, but I guess that's very similar to hiding it...
...
How do I get the day of the week with Foundation?
...
outputs current day of week as a string in locale dependent on current regional settings.
To get just a week day number you must use NSCalendar class:
NSCalendar *gregorian = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSDateComponents *comps = [gregorian co...
How can I get a precise time, for example in milliseconds in Objective-C?
...meInterval is in seconds, but it uses the double to give you greater precision.
In order to calculate millisecond time accuracy, you can do:
// Get a current time for where you want to start measuring from
NSDate *date = [NSDate date];
// do work...
// Find elapsed time and convert to millisecon...
Comment the interface, implementation or both?
...inciple as with code:
on interface, document the interface
on implementation, document the implementation specifics
Java specific: when documenting the implementation, use {@inheritDoc} tag to "include" javadocs from the interface.
For more information:
Official javadoc documentation
Some uno...
When is the thread pool used?
...derstanding of how node works isn't correct... but it's a common misconception, because the reality of the situation is actually fairly complex, and typically boiled down to pithy little phrases like "node is single threaded" that over-simplify things.
For the moment, we'll ignore explicit multi-pr...
How to Deal with Temporary NSManagedObject instances?
...OTE: This answer is very old. See comments for full history. My recommendation has since changed and I no longer recommend using unassociated NSManagedObject instances. My current recommendation is to use temporary child NSManagedObjectContext instances.
Original Answer
The easiest way to do this ...
How to read a .xlsx file using the pandas Library in iPython?
...
I usually create a dictionary containing a DataFrame for every sheet:
xl_file = pd.ExcelFile(file_name)
dfs = {sheet_name: xl_file.parse(sheet_name)
for sheet_name in xl_file.sheet_names}
Update: In pandas version 0.21.0+ you will ...