大约有 35,100 项符合查询结果（耗时：0.0458秒） [XML]
Is there any difference between GROUP BY and DISTINCT
...ates an execution plan as if you'd simply used "Distinct."
However, I think it's important to note Hank's response as well - cavalier treatment of "Group By" and "Distinct" could lead to some pernicious gotchas down the line if you're not careful. It's not entirely correct to say that this is "not...
How do I create a variable number of variables?
...
You can use dictionaries to accomplish this. Dictionaries are stores of keys and values.
>>> dct = {'x': 1, 'y': 2, 'z': 3}
>>> dct
{'y': 2, 'x': 1, 'z': 3}
>>> dct["y"]
2
You can use variable key names to achieve the effect of variable variables without the securit...
How do I add a Maven dependency in Eclipse?
I don't know how to use Maven at all. I've been developing for a couple years with Eclipse and haven't yet needed to know about it. However, now I'm looking at some docs that suggest I do the following:
...
Finish an activity from another activity
I want to finish one activity from another activity, like:
10 Answers
10
...
How to pick a new color for each plotted line within a figure in matplotlib?
I'd like to NOT specify a color for each plotted line, and have each line get a distinct color. But if I run:
7 Answers
...
What is the rationale for fread/fwrite taking size and count as arguments?
We had a discussion here at work regarding why fread and fwrite take a size per member and count and return the number of members read/written rather than just taking a buffer and size. The only use for it we could come up with is if you want to read/write an array of structs which aren't evenly div...
How to deselect a selected UITableView cell?
I am working on a project on which I have to preselect a particular cell.
24 Answers
2...
How do I check if an element is hidden in jQuery?
...tion refers to a single element, this code might be more suitable:
// Checks CSS content for display:[none|block], ignores visibility:[true|false]
$(element).is(":visible");
// The same works with hidden
$(element).is(":hidden");
It is the same as twernt's suggestion, but applied to a single ele...
iOS change navigation bar title font and color
...igationController?.navigationBar.titleTextAttributes =
[NSAttributedString.Key.foregroundColor: UIColor.red,
NSAttributedString.Key.font: UIFont(name: "mplus-1c-regular", size: 21)!]
Edit: Swift 4
self.navigationController?.navigationBar.titleTextAttributes =
[NSAttributedStringKey.foregroundCol...
How to reshape data from long to wide format
...
ChaseChase
59.5k1515 gold badges131131 silver badges157157 bronze badges
...