大约有 42,000 项符合查询结果（耗时：0.0481秒） [XML]
Python pandas Filtering out nan from a data selection of a column of strings
...NaN:
In [87]:
nms
Out[87]:
movie name rating
0 thg John 3
1 thg NaN 4
3 mol Graham NaN
4 lob NaN NaN
5 lob NaN NaN
[5 rows x 3 columns]
In [89]:
nms = nms.dropna(thresh=2)
In [90]:
nms[nms.name.notnull()]
Out[90]:
movie name rating
0...
What is the bower (and npm) version syntax?
...
342
In a nutshell, the syntax for Bower version numbers (and NPM's) is called SemVer, which is sho...
Correct way to define C++ namespace methods in .cpp file
...se it shows that in the namespace, you are defining the function.
Version 3 is right also because you used the :: scope resolution operator to refer to the MyClass::method () in the namespace ns1. I prefer version 3.
See Namespaces (C++). This is the best way to do this.
...
Check if two unordered lists are equal [duplicate]
...
463
Python has a built-in datatype for an unordered collection of (hashable) things, called a set. I...
Is there an R function for finding the index of an element in a vector?
... function match works on vectors :
x <- sample(1:10)
x
# [1] 4 5 9 3 8 1 6 10 7 2
match(c(4,8),x)
# [1] 1 5
match only returns the first encounter of a match, as you requested. It returns the position in the second argument of the values in the first argument.
For multiple matching, ...
Constantly print Subprocess output while process is running
...
13 Answers
13
Active
...
Remove ActiveRecord in Rails 3
Now that Rails 3 beta is out, I thought I'd have a look at rewriting an app I have just started work on in Rails 3 beta, both to get a feel for it and get a bit of a head-start. The app uses MongoDB and MongoMapper for all of its models and therefore has no need for ActiveRecord. In the previous ver...
How to round to 2 decimals with Python?
...
answered Dec 8 '13 at 18:20
roliszrolisz
5,41011 gold badge1515 silver badges1414 bronze badges
...
Delete files older than 3 months old in a directory using .NET
...o know (using C#) how I can delete files in a certain directory older than 3 months, but I guess the date period could be flexible.
...
Take the content of a list and append it to another list
...
379
You probably want
list2.extend(list1)
instead of
list2.append(list1)
Here's the differen...