大约有 48,000 项符合查询结果（耗时：0.0442秒） [XML]
Checking for empty queryset in Django
...if not my_objects: to demonstrate that this is how they do it in the docs. All else is utterly irrelevant so I do not get your point. They could as well make a thousand queries and it would still be totally irrelevant as this is not the point of this answer, with which I make clear that I agree.
...
How do I find files with a path length greater than 260 characters in Windows?
...
See my answer for a way to achieve this in powershell, allowing you to either find the offending file names (those above 260 characters) or alternatively, ignore them.
– Jonno
Oct 18 '15 at 12:11
...
Is there a MySQL option/feature to track history of changes to records?
...ant to audit the changes to the data - who did what and when?", you can usually use audit tables (as per the trigger example Keethanjan posted). I'm not a huge fan of triggers, but it has the great benefit of being relatively painless to implement - your existing code doesn't need to know about the ...
How to sort an IEnumerable
How can I sort an IEnumerable<string> alphabetically. Is this possible?
4 Answers
...
How to use base class's constructors and assignment operator in C++?
...
You can explicitly call constructors and assignment operators:
class Base {
//...
public:
Base(const Base&) { /*...*/ }
Base& operator=(const Base&) { /*...*/ }
};
class Derived : public Base
{
int additional_;
public:
...
How can I check if a string represents an int, without using try/except?
...
If you're really just annoyed at using try/excepts all over the place, please just write a helper function:
def RepresentsInt(s):
try:
int(s)
return True
except ValueError:
return False
>>> pri...
Serializing class instance to JSON
...ps() only knows how to serialize a limited set of object types by default, all built-in types. List here: https://docs.python.org/3.3/library/json.html#encoders-and-decoders
One good solution would be to make your class inherit from JSONEncoder and then implement the JSONEncoder.default() function...
Converting any string into camel case
...
Looking at your code, you can achieve it with only two replace calls:
function camelize(str) {
return str.replace(/(?:^\w|[A-Z]|\b\w)/g, function(word, index) {
return index === 0 ? word.toLowerCase() : word.toUpperCase();
}).replace(/\s+/g, '');
}
camelize("EquipmentClass name"...
Linq to Sql: Multiple left outer joins
...
This may be cleaner (you dont need all the into statements):
var query =
from order in dc.Orders
from vendor
in dc.Vendors
.Where(v => v.Id == order.VendorId)
.DefaultIfEmpty()
from status
in dc.Status
.Where(...
What is the use of join() in Python threading?
...t clumsy ascii-art to demonstrate the mechanism:
The join() is presumably called by the main-thread. It could also be called by another thread, but would needlessly complicate the diagram.
join-calling should be placed in the track of the main-thread, but to express thread-relation and keep it as s...