大约有 45,000 项符合查询结果（耗时：0.0694秒） [XML]
How to make a flat list out of list of lists?
...for item in sublist]
As evidence, you can use the timeit module in the standard library:
$ python -mtimeit -s'l=[[1,2,3],[4,5,6], [7], [8,9]]*99' '[item for sublist in l for item in sublist]'
10000 loops, best of 3: 143 usec per loop
$ python -mtimeit -s'l=[[1,2,3],[4,5,6], [7], [8,9]]*99' 'sum(l...
Extract first item of each sublist
... the best way to extract the first item of each sublist in a list of lists and append it to a new list. So if I have:
7 Ans...
When do you use varargs in Java?
...at("This is an integer: %d", myInt);
String.format("This is an integer: %d and a string: %s", myInt, myString);
share
|
improve this answer
|
follow
|
...
How can the Euclidean distance be calculated with NumPy?
...roduction to Data Mining
This works because Euclidean distance is l2 norm and the default value of ord parameter in numpy.linalg.norm is 2.
share
|
improve this answer
|
f...
When should I use Arrow functions in ECMAScript 6?
...ght about code style in the context of the upcoming ECMAScript 6 (Harmony) and who have already worked with the language.
9...
How to print like printf in Python3?
...
In both versions, % is an operator which requires a string on the left-hand side and a value or a tuple of values or a mapping object (like dict) on the right-hand side.
So, your line ought to look like this:
print("a=%d,b=%d" % (f(x,n),g(x,n)))
Also, the recommendation for Python3 and newer ...
Add alternating row color to SQL Server Reporting services report
...
Go to the table row's BackgroundColor property and choose "Expression..."
Use this expression:
= IIf(RowNumber(Nothing) Mod 2 = 0, "Silver", "Transparent")
This trick can be applied to many areas of the report.
And in .NET 3.5+ You could use:
= If(RowNumber(Nothing...
Is Hash Rocket deprecated?
...
The author of that blog post is being overly dramatic and foolish, the => is still quite necessary. In particular:
You must use the rocket for symbols that are not valid labels: :$set => x is valid but $set: x is not. In Ruby 2.2+ you can get around this problem with quo...
Sending multipart/formdata with jQuery.ajax
...P native array instead of a counter
Just name your file elements the same and end the name in brackets:
jQuery.each(jQuery('#file')[0].files, function(i, file) {
data.append('file[]', file);
});
$_FILES['file'] will then be an array containing the file upload fields for every file uploaded. ...
What is the difference between Strategy pattern and Dependency Injection?
Strategy pattern and Dependency Injection both allow us to set / inject objects at run time. What is the difference between Strategy pattern and Dependency Injection?
...