大约有 2,253 项符合查询结果（耗时：0.0172秒） [XML]
Why CancellationToken is separate from CancellationTokenSource?
...
That might still result in a crafty programmer casting to CancellationTokenSource. You'd think you could just say "don't do that", but people (including me!) do occasionally do these things anyway to get at some hidden functionality, and it'd happen. That's my current the...
What is the C# equivalent to Java's isInstance()?
...
Depends, use is if you don't want to use the result of the cast and use as if you do. You hardly ever want to write:
if(foo is Bar) {
return (Bar)foo;
}
Instead of:
var bar = foo as Bar;
if(bar != null) {
return bar;
}
...
How can I get the SQL of a PreparedStatement?
...
It doesn't work and throws ClassCastException: java.lang.ClassCastException: oracle.jdbc.driver.T4CPreparedStatement cannot be cast to com.mysql.jdbc.JDBC4PreparedStatement
– Ercan
Apr 4 '19 at 13:15
...
Why is the default value of the string type null instead of an empty string?
..., and (2) an unfortunate extra layer of boxing indirection any time it was cast to Object. Given that the heap representation of string is unique, having special treatment to avoid extra boxing wouldn't have been much of a stretch (actually, being able to specify non-default boxing behaviors would ...
Why is Multiple Inheritance not allowed in Java or C#?
...s a lot of complexity into the
implementation. This complexity
impacts casting, layout, dispatch,
field access, serialization, identity
comparisons, verifiability,
reflection, generics, and probably
lots of other places.
You can read the full article here.
For Java, you can read th...
How to avoid warning when introducing NAs by coercion
...Not the answer you're looking for? Browse other questions tagged r parsing casting na or ask your own question.
GSON throwing “Expected BEGIN_OBJECT but was BEGIN_ARRAY”?
...u don't. You have an array of objects of your type. You can't just try and cast the result like that and expect it to magically work ;)
The User guide for Gson Explains how to deal with this:
https://github.com/google/gson/blob/master/UserGuide.md
This will work:
ChannelSearchEnum[] enums = gson...
How do I get a plist as a Dictionary in Swift?
... type Array<AnyObject>, but we know what type it really is so we can cast it to the correct type:
let dictArray = plist as! [[String:String]]
// [[String:String]] is equivalent to Array< Dictionary<String, String> >
And now we can access the various properties of our Array of St...
Reshaping data.frame from wide to long format
...
reshape() takes a while to get used to, just as melt/cast. Here is a solution with reshape, assuming your data frame is called d:
reshape(d,
direction = "long",
varying = list(names(d)[3:7]),
v.names = "Value",
idvar = c("Code", "Country"),
...
Zero-pad digits in string
I need to cast single figures (1 to 9) to (01 to 09). I can think of a way but its big and ugly and cumbersome. I'm sure there must be some concise way. Any Suggestions
...