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Which is better in python, del or delattr?
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272
The first is more efficient than the second. del foo.bar compiles to two bytecode instruction...
How to format a floating number to fixed width in Python
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525
for x in numbers:
print "{:10.4f}".format(x)
prints
23.2300
0.1233
1.0000
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What is external linkage and internal linkage?
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288
When you write an implementation file (.cpp, .cxx, etc) your compiler generates a translation ...
Why can't I initialize non-const static member or static array in class?
...a is allowed to be initialized while others are not.
Reference:
C++03 9.4.2 Static data members
§4
If a static data member is of const integral or const enumeration type, its declaration in the class definition can specify a constant-initializer which shall be an integral constant expression (...
Embedding JavaScript engine into .NET [closed]
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21 Answers
21
Active
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warning: [options] bootstrap class path not set in conjunction with -source 1.5
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102
From a blog post:
To use javac from JDK N to cross-compiler to an older platform version, th...
Efficiently test if a port is open on Linux?
...>&6
cat <&6
I'm using 6 as the file descriptor because 0,1,2 are stdin, stdout, and stderr. 5 is sometimes used by Bash for child processes, so 3,4,6,7,8, and 9 should be safe.
As per the comment below, to test for listening on a local server in a script:
exec 6<>/dev/tcp/127...
Subset of rows containing NA (missing) values in a chosen column of a data frame
...data frame DF has columns that contain observed values and a column ( VaR2 ) that contains the date at which a measurement has been taken. If the date was not recorded, the CSV file contains the value NA , for missing data.
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What happens if I define a 0-size array in C/C++?
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An array cannot have zero size.
ISO 9899:2011 6.7.6.2:
If the expression is a constant expression, it shall have a value greater than zero.
The above text is true both for a plain array (paragraph 1). For a VLA (variable length array), the behavior is undefine...
Can I export a variable to the environment from a bash script without sourcing it?
...ble, print commands that will set the environment variable:
$ cat set-vars2.sh
#!/bin/bash
echo export FOO=BAR
$ eval "$(./set-vars2.sh)"
$ echo "$FOO"
BAR
A third approach is to have a script that sets your environment variable(s) internally and then invokes a specified command with that environ...