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Find object in list that has attribute equal to some value (that meets any condition)
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next((x for x in test_list if x.value == value), None)
This gets the first item from the list that matches the condition, and returns None if no item matches. It's my preferred single-expression form.
However,
for x in test_list:
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How can I filter a date of a DateTimeField in Django?
...te operator. Check "#9596 Comparing a DateTimeField to a date is too hard" for more details.
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Any reason not to use '+' to concatenate two strings?
...is is bad because the Python interpreter has to create a new string object for each iteration, and it ends up taking quadratic time. (Recent versions of CPython can apparently optimize this in some cases, but other implementations can't, so programmers are discouraged from relying on this.) ''.join...
What to put in a python module docstring? [closed]
... I've read both PEP 8 and PEP 257 , and I've written lots of docstrings for functions and classes, but I'm a little unsure about what should go in a module docstring. I figured, at a minimum, it should document the functions and classes that the module exports, but I've also seen a few modules t...
Reload Flask app when template file changes
...th, walk
extra_dirs = ['directory/to/watch',]
extra_files = extra_dirs[:]
for extra_dir in extra_dirs:
for dirname, dirs, files in walk(extra_dir):
for filename in files:
filename = path.join(dirname, filename)
if path.isfile(filename):
extra_file...
How to determine a Python variable's type?
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You may be looking for the type() built-in function.
See the examples below, but there's no "unsigned" type in Python just like Java.
Positive integer:
>>> v = 10
>>> type(v)
<type 'int'>
Large positive integer:
&g...
How to check iOS version?
...OS 9, *) {}
In Objective-C, you need to check the system version and perform a comparison.
[[NSProcessInfo processInfo] operatingSystemVersion] in iOS 8 and above.
As of Xcode 9:
if (@available(iOS 9, *)) {}
The full answer …
In Objective-C, and Swift in rare cases, it's better to avoid ...
Removing duplicate objects with Underscore for Javascript
...t {a=2}, Object {a=3}, Object {a=4}]
Notes:
Callback return value used for comparison
First comparison object with unique return value used as unique
underscorejs.org demonstrates no callback usage
lodash.com shows usage
Another example :
using the callback to extract car makes, colors from a...
Recommended way of making React component/div draggable
...it's state, and the draggable would "snap back" to it's initial position before dragging.
Mixin or component?
@ssorallen pointed out that, because "draggable" is more an attribute than a thing in itself, it might serve better as a mixin. My experience with mixins is limited, so I haven't seen how ...
Best way to require all files from a directory in ruby?
... It's probably safer to use File.join rather than making assumptions about forward/backward slashes: Dir[File.join(File.dirname(__FILE__), 'lib', '*.rb')].each {|file| require file }
– Chris
Jul 6 '12 at 23:22
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