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Why does the C++ map type argument require an empty constructor when using []?
... default object
data_type().
If you don't have default constructor you can use insert/find functions.
Following example works fine:
myMap.insert( std::map< int, MyClass >::value_type ( 1, MyClass(1) ) );
myMap.find( 1 )->second;
...
When should I use @classmethod and when def method(self)?
...ect - you understand how classmethods work.
The why is that these methods can be called both on an instance OR on the class (in both cases, the class object will be passed as the first argument):
class Dummy(object):
@classmethod
def some_function(cls,*args,**kwargs):
print cls
#...
datetime dtypes in pandas read_csv
...s not work
There is no datetime dtype to be set for read_csv as csv files can only contain strings, integers and floats.
Setting a dtype to datetime will make pandas interpret the datetime as an object, meaning you will end up with a string.
Pandas way of solving this
The pandas.read_csv() funct...
Html code as IFRAME source rather than a URL
...
You can do this with a data URL. This includes the entire document in a single string of HTML. For example, the following HTML:
<html><body>foo</body></html>
can be encoded as this:
data:text/html;ch...
Open Graph namespace declaration: HTML with XMLNS or head prefix?
...licting information on how to best implement Open Graph namespaces. Specifically, the Open Graph website uses a few different methods, and the Facebook Open Graph examples use other methods.
...
Why can I create a class named “var”?
Isn't var a keyword in C#? But why can I do this:
5 Answers
5
...
Django REST framework: non-model serializer
...t, post, delete operations). Instead, it provides other services with some calculation results. On a request my service makes some calculations and just returns the results back (doesn't store the results in its own database).
...
Applying function with multiple arguments to create a new pandas column
...
Alternatively, you can use numpy underlying function:
>>> import numpy as np
>>> df = pd.DataFrame({"A": [10,20,30], "B": [20, 30, 10]})
>>> df['new_column'] = np.multiply(df['A'], df['B'])
>>> df
A B ...
Jump to matching XML tags in Vim
...
There is a vim plugin called matchit.vim . You can find it here: http://www.vim.org/scripts/script.php?script_id=39 . It was created pretty much the exact purpose you describe.
Install that, place your cursor on the body of the tag (not the <&...
Operation on every pair of element in a list
...product() generates every possible pairing of elements, including all duplicates:
1,1 1,2 1,3 1,4
2,1 2,2 2,3 2,4
3,1 3,2 3,3 3,4
4,1 4,2 4,3 4,4
permutations() generates all unique orderings of each unique pair of elements, eliminating the x,x duplicates:
. 1,2 1,3 1,4
2,1 . ...