大约有 47,000 项符合查询结果（耗时：0.0485秒） [XML]
if A vs if A is not None:
... method returns None if there were no rows in the result. Suppose you were selecting a value that might return 0 and need to know whether it's actually 0 or whether the query had no results at all.
A common idiom is to give a function or method's optional argument the default value of None, and the...
How do I split a string with multiple separators in javascript?
...+/)
Hello,awesome,world!
Edited to add:
You can get the last element by selecting the length of the array minus 1:
>>> bits = "Hello awesome, world!".split(/[\s,]+/)
["Hello", "awesome", "world!"]
>>> bit = bits[bits.length - 1]
"world!"
... and if the pattern doesn't match:
...
Django - filtering on foreign key properties
...
Is this going to hit the DB twice, should I be using select_related() to make this more optimal?
– Fraser Graham
Dec 30 '09 at 22:52
5
...
Extract subset of key-value pairs from Python dictionary object?
...
This answer uses a dictionary comprehension similar to the selected answer, but will not except on a missing item.
python 2 version:
{k:v for k, v in bigDict.iteritems() if k in ('l', 'm', 'n')}
python 3 version:
{k:v for k, v in bigDict.items() if k in ('l', 'm', 'n')}
...
How to change time and timezone in iPhone simulator?
...tiple different time zones: add a TZ setting for each one, but remember to select only one at a time. I just added America/Chicago, Europe/Istanbul, Asia/Hong_Kong, and Pacific/Honolulu to get an assortment so I can track down a timezone-dependent bug. This will NOT work if you need to capture scree...
Jquery mouseenter() vs mouseover()
...ever, the mouseenter event only triggers when the mouse pointer enters the selected element. The mouseover event is triggered if a mouse pointer enters any child elements as well.
share
|
improve th...
Gradle build only one module
...e a wrapper for subprojects that has no gradle file of its own. Unlike the selected answer, this works for me. Also thanks for clarification in comment, could you add it to the answer?
– Vlasec
Sep 10 '15 at 15:10
...
How to filter (key, value) with ng-repeat in AngularJs?
...s can only be applied to arrays and not objects, from angular's API -
"Selects a subset of items from array and returns it as a new array."
You have two options here:
1) move $scope.items to an array or -
2) pre-filter the ng-repeat items, like this:
<div ng-repeat="(k,v) in filterSecId(it...
Python time measure function
....time() - start
return ret, elapsed
timed(lambda: database.foo.execute('select count(*) from source.apachelog'))
(<sqlalchemy.engine.result.ResultProxy object at 0x7fd6c20fc690>, 4.07547402381897)
share
|
...
How do I convert a String object into a Hash object?
...
This answer should be selected for avoiding using eval.
– Michael_Zhang
Sep 4 '18 at 21:57
4
...