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Use cases for the 'setdefault' dict method
...e case: Grouping items (in unsorted data, else use itertools.groupby)
# really verbose
new = {}
for (key, value) in data:
if key in new:
new[key].append( value )
else:
new[key] = [value]
# easy with setdefault
new = {}
for (key, value) in data:
group = new.setdefault(k...
Does reading an entire file leave the file handle open?
...hat on the particular Python implementation.
To understand what this is all about, pay particular attention to the actual file object. In your code, that object is mentioned only once, in an expression, and becomes inaccessible immediately after the read() call returns.
This means that the file...
How to join components of a path when you are constructing a URL in Python
...
Specifically once I have that the prefix has to ends in / and that the target path can't begin in / I might as well just concatenate. In this case I am not sure if urljoin is really helping?
– amjoconn
...
Separation of business logic and data access in django
...de is confusing and, after a certain time, I cease to understand what is really happening.
10 Answers
...
Does Python have a string 'contains' substring method?
...methods to make in available to your custom type.
– BallpointBen
Aug 17 '18 at 7:02
31
Just make ...
Length of generator output [duplicate]
... Fibonacci numbers. You can get as many Fibonacci numbers as you want by calling next().
If you really need to know the number of items there are, then you can't iterate through them linearly one time anyway, so just use a different data structure such as a regular list.
...
How can I use PowerShell with the Visual Studio Command Prompt?
...
Stealing liberally from here: http://allen-mack.blogspot.com/2008/03/replace-visual-studio-command-prompt.html, I was able to get this to work. I added the following to my profile.ps1 and all is well with the world.
pushd 'c:\Program Fil...
Error handling in Bash
...kens code's predictability and portability).
You can either let the trap call error for you (in which case it uses the default exit code of 1 and no message) or call it yourself and provide explicit values; for instance:
error ${LINENO} "the foobar failed" 2
will exit with status 2, and give an ...
multiprocessing.Pool: When to use apply, apply_async or map?
...
Back in the old days of Python, to call a function with arbitrary arguments, you would use apply:
apply(f,args,kwargs)
apply still exists in Python2.7 though not in Python3, and is generally not used anymore. Nowadays,
f(*args,**kwargs)
is preferred. The...
GET URL parameter in PHP
...perglobal: a built-in variable that's populated by PHP and is available in all scopes (you can use it from inside a function without the global keyword).
Since the variable might not exist, you could (and should) ensure your code does not trigger notices with:
<?php
if (isset($_GET['link'])) {
...