大约有 40,000 项符合查询结果（耗时：0.0573秒） [XML]
Curly braces in string in PHP
...nterpolation. From the manual:
Complex (curly) syntax
This isn't called complex because the syntax is complex, but because
it allows for the use of complex expressions.
Any scalar variable, array element or object property with a string
representation can be included via this synta...
Selecting multiple columns in a pandas dataframe
...).
df1 = df[['a', 'b']]
Alternatively, if it matters to index them numerically and not by their name (say your code should automatically do this without knowing the names of the first two columns) then you can do this instead:
df1 = df.iloc[:, 0:2] # Remember that Python does not slice inclusive of...
How to post data in PHP using file_get_contents?
...Sending an HTTP POST request using file_get_contents is not that hard, actually : as you guessed, you have to use the $context parameter.
There's an example given in the PHP manual, at this page : HTTP context options (quoting) :
$postdata = http_build_query(
array(
'var1' => 'some...
.gitignore all the .DS_Store files in every folder and subfolder
...k the problem you're having is that in some earlier commit, you've accidentally added .DS_Store files to the repository. Of course, once a file is tracked in your repository, it will continue to be tracked even if it matches an entry in an applicable .gitignore file.
You have to manually remove th...
How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?
Is there a way to call a block with a primitive parameter after a delay, like using performSelector:withObject:afterDelay: but with an argument like int / double / float ?
...
How do I override __getattr__ in Python without breaking the default behavior?
I want to override the __getattr__ method on a class to do something fancy but I don't want to break the default behavior.
...
Select distinct values from a table field
...ant any ordering to be applied to a query, not even the default ordering, call order_by() with no parameters.
and distinct() in the note where it discusses issues with using distinct() with ordering.
To query your DB, you just have to call:
models.Shop.objects.order_by().values('city').distinct(...
Compile time string hashing
... string length, and the compiler is not clever enough to elide the second call. Check other answers for possible fix for this problem.
– CygnusX1
Feb 27 '16 at 16:34
...
How to extract the year from a Python datetime object?
...ew times and you'll be prompted with the members of the "now" object:
now.__add__ now.__gt__ now.__radd__ now.__sub__ now.fromordinal now.microsecond now.second now.toordinal now.weekday
now.__class__ now.__hash__ ...
Vagrant error : Failed to mount folders in Linux guest
...
The plugin vagrant-vbguest solved my problem:
$ vagrant plugin install vagrant-vbguest
Output:
$ vagrant reload
==> default: Attempting graceful shutdown of VM...
...
==> default: Machine booted and ready!
GuestAdditions 4.3.12 running --- OK.
==> default: Checking for guest addi...