大约有 16,000 项符合查询结果（耗时：0.0395秒） [XML]
Counting the number of elements with the values of x in a vector
... 1 1 1
Then you can subset it:
> a[names(a)==435]
435
3
Or convert it into a data.frame if you're more comfortable working with that:
> as.data.frame(table(numbers))
numbers Freq
1 4 2
2 5 1
3 23 2
4 34 2
...
...
Monad in plain English? (For the OOP programmer with no FP background)
...To clarify the kind of understanding I was looking for, let's say you were converting an FP application that had monads into an OOP application. What would you do to port the responsibilities of the monads into the OOP app?
Most OOP languages do not have a rich enough type system to represent the ...
How does the getView() method work when creating your own custom adapter?
...it can be used for one of the new Views appearing. This reused View is the convertView. If this is null it means that there is no recycled View and we have to create a new one, otherwise we should use it to avoid creating a new.
3: The parent is provided so you can inflate your view into that for p...
How did Google manage to do this? Slide ActionBar in Android application
... items;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View rowView = convertView;
if (rowView == null) {
LayoutInflater inflater = act.getLayoutInflater();
rowView = inflater.inflate(R.layout.menu_listitem,...
What is the definition of “interface” in object oriented programming
...or. However, Java 8 introduced lambda expressions so the C# example can be converted to Java very easily (Func<int> becomes java.util.function.IntSupplier and => becomes ->).
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Catching an exception while using a Python 'with' statement
... thus differentiate between the different potential error sources:
import sys
try:
mgr = ContextManager()
except ValueError as err:
print('__init__ raised:', err)
else:
try:
value = type(mgr).__enter__(mgr)
except ValueError as err:
print('__enter__ raised:', err)
...
Purpose of Unions in C and C++
...inter which cannot be used as a pointer of its own type, but must first be converted back to a pointer to the enclosing type or a character type. Any remotely-workable compiler will extend the language by making more things work than...
– supercat
Jun 28 '16 a...
Base64: What is the worst possible increase in space usage?
...f a server received a base64 string and wanted to check it's length before converting,, say it wanted to always permit the final byte array to be 16KB. How big could a 16KB byte array possibly become when converted to a Base64 string (assuming one byte per character)?
...
Parcelable encountered IOException writing serializable object getactivity()
... to get image. I've already set it before and now I just get it first than convert it and pass it separatly:
Bitmap image = selectedItem.getPlacePhoto();
image.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] byteArray = stream.toByteArray();
Intent intent = new Intent(YourPresentActivi...
What's the difference between comma separated joins and join on syntax in MySQL? [duplicate]
...istakenly forget comma in comma-separated join, second table automatically convert to table alias for first table. Not in all cases, but there is chances for something like this
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