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Increment a database field by 1
...say logins, how would I go about updating that field by 1 within a sql command?
5 Answers
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How to avoid having class data shared among instances?
...ring the variables inside the class declaration makes them "class" members and not instance members. Declaring them inside the __init__ method makes sure that a new instance of the members is created alongside every new instance of the object, which is the behavior you're looking for.
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Python's equivalent of && (logical-and) in an if-statement
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You would want and instead of &&.
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What's the difference between lists enclosed by square brackets and parentheses in Python?
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for the above 'y=x' example , list and tuple behave in the same way now (verified in python3.8.5)
– Youjun Hu
Aug 15 at 9:11
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How to pass macro definition from “make” command line arguments (-D) to C source code?
I usually pass macro definitions from "make command line" to a "makefile" using the option :
-Dname=value. The definition is accessible inside the makefile.
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Random row selection in Pandas dataframe
Is there a way to select random rows from a DataFrame in Pandas.
6 Answers
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How to access pandas groupby dataframe by key
... answered Feb 6 '13 at 17:00
Andy HaydenAndy Hayden
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What is null in Java?
...ceof operator is true if the value of the RelationalExpression is not null and the reference could be cast to the ReferenceType without raising a ClassCastException. Otherwise the result is false.
This means that for any type E and R, for any E o, where o == null, o instanceof R is always false.
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Capturing Ctrl-c in ruby
...t. When a control-C comes in, it raises Interrupt. Since both SystemExit and Interrupt derive from Exception, your exception handling is stopping the exit or interrupt in its tracks. Here's the fix:
Wherever you can, change
rescue Exception => e
# ...
end
to
rescue StandardError => ...
ExpressJS How to structure an application?
...pp that is too big to effectively work on. Get fancy for BIG wins, not for converting 3 simple lines to 1 complex line.
Use lower-kebab-case filenames
This format avoids filesystem case sensitivity issues across platforms
npm forbids uppercase in new package names, and this works well with that
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