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What is the difference between PS1 and PROMPT_COMMAND
...$(~/bin/bash_prompt)
}
export PROMPT_COMMAND=prompt_command
Then write a script (bash, perl, ruby: your choice), and place it in ~/bin/bash_prompt.
The script can use any information it likes to construct a prompt. This is much simpler IMO because you don't have to learn the somewhat baroque subs...
When is “i += x” different from “i = i + x” in Python?
...
This depends entirely on the object i.
+= calls the __iadd__ method (if it exists -- falling back on __add__ if it doesn't exist) whereas + calls the __add__ method1 or the __radd__ method in a few cases2.
From an API perspective, __iadd__ is supposed to be used fo...
How to run code when a class is subclassed? [duplicate]
...- Watcher subclasses type, not object. 2 - SuperClass has no superclass at all, not object. I'm just so used to writing down object as a superclass for every class I defined that I somehow missed it that this code was using something else. Although there doesn't seem to be any harm in making SuperCl...
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.al
I just discovered a logical bug in my code which was causing all sorts of problems. I was inadvertently doing a bitwise AND instead of a logical AND .
...
In practice, what are the main uses for the new “yield from” syntax in Python 3.3?
...or v in g: yield v does not even begin to do justice to what yield from is all about. Because, let's face it, if all yield from does is expand the for loop, then it does not warrant adding yield from to the language and preclude a whole bunch of new features from being implemented in Python 2.x.
Wh...
What are the most common naming conventions in C?
...I follow the GTK+ coding convention, which can be summarized as follows:
All macros and constants in caps: MAX_BUFFER_SIZE, TRACKING_ID_PREFIX.
Struct names and typedef's in camelcase: GtkWidget, TrackingOrder.
Functions that operate on structs: classic C style: gtk_widget_show(), tracking_order_p...
How do I include a pipe | in my linux find -exec command?
...ld result in only a single agrep process being spawned which would process all the output produced by numerous invocations of zcat.
If you for some reason would like to invoke agrep multiple times, you can do:
find . -name 'file_*' -follow -type f \
-printf "zcat %p | agrep -dEOE 'grep'\n" | s...
Getting distance between two points based on latitude/longitude
...just on answering the specific bug OP ran into.
It's because in Python, all the trig functions use radians, not degrees.
You can either convert the numbers manually to radians, or use the radians function from the math module:
from math import sin, cos, sqrt, atan2, radians
# approximate radiu...
How to get the day of week and the month of the year?
I don't know much about Javascript, and the other questions I found are related to operations on dates, not only getting the information as I need it.
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Why doesn't Python have a sign function?
... it wasn't accepted, because they didn't agree on what it should return in all the edge cases (+/-0, +/-nan, etc)
So they decided to implement only copysign, which (although more verbose) can be used to delegate to the end user the desired behavior for edge cases - which sometimes might require the...