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Accessing class variables from a list comprehension in the class definition
...lowing will fail:
class A:
a = 42
b = list(a + i for i in range(10))
So, to summarize: you cannot access the class scope from functions, list comprehensions or generator expressions enclosed in that scope; they act as if that scope does not exist. In Python 2, list comprehensions were ...
Count occurrences of a char in plain text file
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178
How about this:
fgrep -o f <file> | wc -l
Note: Besides much easier to remember/dupli...
Export database schema into SQL file
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150
You can generate scripts to a file via SQL Server Management Studio, here are the steps:
Rig...
How to sort a dataFrame in python pandas by two or more columns?
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As of the 0.17.0 release, the sort method was deprecated in favor of sort_values. sort was completely removed in the 0.20.0 release. The arguments (and results) remain the same:
df.sort_values(['a', 'b'], ascending=[True, False])
Y...
promise already under evaluation: recursive default argument reference or earlier problems?
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164
Formal arguments of the form x=x cause this. Eliminating the two instances where they occur w...
Find the PID of a process that uses a port on Windows
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218
Just open a command shell and type (saying your port is 123456):
netstat -a -n -o | find "1234...
What is a bank conflict? (Doing Cuda/OpenCL programming)
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105
For nvidia (and amd for that matter) gpus the local memory is divided into memorybanks. Each b...
How to install Android SDK Build Tools on the command line?
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Adding 'serial' to existing column in Postgres
...imary key) which currently contains unique sequential integers starting at 1, but which was not created using the 'serial' keyword.
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