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Date query with ISODate in mongodb doesn't seem to work
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Error running query. Reason: (invalid_operator) Invalid operator: $date
– saber tabatabaee yazdi
Sep 13 '18 at 16:49
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When to use thread pool in C#? [closed]
...l vs. create my own threads. One book recommends using a thread pool for small tasks only (whatever that means), but I can't seem to find any real guidelines. What are some considerations you use when making this programming decision?
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INT 10H 中断介绍 - C/C++ - 清泛网 - 专注C/C++及内核技术
INT 10H 中断介绍int_10h_instructionsINT 10H 是由 BIOS 对屏幕及显示器所提供的服务程序，而后倚天公司针对倚天中文提供了许多服务程序，这些服务程序也加挂在 INT 10H ...
INT 10H 是由 BIOS 对屏幕及显示器所提供的服务程序。使用 INT 10H...
How to get the filename without the extension from a path in Python?
...hould merit it's own official command? Something like os.path.filename(path_to_file) instead of os.path.splitext(os.path.basename(path_to_file))[0]
– Fnord
Jul 2 '14 at 17:13
20
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Swift to Objective-C header not created in Xcode 6
...Defines Module must be set to Yes in Build Settings, under Packaging.
Finally works. Thanks to everyone for the help :-)
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NSDate beginning of day and end of day
...o: noon)!
let specificDate = Date("2020-01-01")
extension Date {
init(_ dateString:String) {
let dateStringFormatter = DateFormatter()
dateStringFormatter.dateFormat = "yyyy-MM-dd"
dateStringFormatter.locale = NSLocale(localeIdentifier: "en_US_POSIX") as Locale
l...
How to take a screenshot programmatically on iOS
...iOS7 or above
- (UIImage *) screenshot {
CGSize size = CGSizeMake(your_width, your_height);
UIGraphicsBeginImageContextWithOptions(size, NO, [UIScreen mainScreen].scale);
CGRect rec = CGRectMake(0, 0, your_width, your_height);
[_viewController.view drawViewHierarchyInRect:rec afte...
Difference between std::system_clock and std::steady_clock?
...11.7.1 [time.clock.system]/1:
Objects of class system_clock represent wall clock time from the system-wide realtime clock.
20.11.7.2 [time.clock.steady]/1:
Objects of class steady_clock represent clocks for which values of time_point never decrease as physical time advances and for which v...
Relative frequencies / proportions with dplyr
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Try this:
mtcars %>%
group_by(am, gear) %>%
summarise(n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vigne...
Determine the number of NA values in a column
...nt the number of NA values in a data frame column. Say my data frame is called df , and the name of the column I am considering is col . The way I have come up with is following:
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