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Selecting multiple columns in a pandas dataframe
...1 = df[['a', 'b']]
Alternatively, if it matters to index them numerically and not by their name (say your code should automatically do this without knowing the names of the first two columns) then you can do this instead:
df1 = df.iloc[:, 0:2] # Remember that Python does not slice inclusive of the ...
What is the use of having destructor as private?
...en "friend"ed) responsible for counting the number of references to itself and delete it when the number hits zero. A private dtor would prevent anybody else from deleting it when there were still references to it.
For another instance, what if you have an object that has a manager (or itself) tha...
How do I clone a generic list in C#?
I have a generic list of objects in C#, and wish to clone the list. The items within the list are cloneable, but there doesn't seem to be an option to do list.Clone() .
...
Add floating point value to android resources/values
I'm trying to add a little space between lines to my TextViews using android:lineSpacingMultiplier
from the documentation :
...
How can I convert a string to a number in Perl?
I have a string which holds a decimal value in it and I need to convert that string into a floating point variable. So an example of the string I have is "5.45" and I want a floating point equivalent so I can add .1 to it. I have searched around the internet, but I only see how to convert a string t...
Access nested dictionary items via a list of keys?
...ataDict, mapList):
return reduce(operator.getitem, mapList, dataDict)
and reuse getFromDict to find the location to store the value for setInDict():
def setInDict(dataDict, mapList, value):
getFromDict(dataDict, mapList[:-1])[mapList[-1]] = value
All but the last element in mapList is need...
How do I add spacing between columns in Bootstrap?
...sistent so that all of your columns line up correctly. To get even spacing and column size I would do the following:
<div class="row">
<div class="col-md-5"></div>
<div class="col-md-5 col-md-offset-2"></div>
</div>
In Bootstrap 4 use: offset-2 or offset-md-2...
Type definition in object literal in TypeScript
...has methods as well as properties? Since the class doesn't get initialized and we only assign properties, calling a method on the class will cause a null exception. Basically, the object we create only 'acts' as the class because we assign its type, but it is not actually an instance of that class. ...
How can I do an UPDATE statement with JOIN in SQL Server?
...to do it in ANSI/ISO (aka should work on any SQL DBMS), MySQL, SQL Server, and Oracle. Be advised that my suggested ANSI/ISO method will typically be much slower than the other two methods, but if you're using a SQL DBMS other than MySQL, SQL Server, or Oracle, then it may be the only way to go (e.g...
Can an int be null in Java?
...areful when unboxing null Integers since this can cause a lot of confusion and head scratching!
e.g. this:
int a = object.getA(); // getA returns a null Integer
will give you a NullPointerException, despite object not being null!
To follow up on your question, if you want to indicate the absen...