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What is the difference between “ is None ” and “ ==None ”
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class Foo:
def __eq__(self,other):
return True
foo=Foo()
print(foo==None)
# True
print(foo is None)
# False
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How to install Java SDK on CentOS?
I have CentOS 5, but I don't know the steps to install Java SDK on Linux.
12 Answers
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How to get Maven project version to the bash command line
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I'm removing all logging (INFO,WARNING,etc) and 'Download' messages with mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version|grep -Ev '(^\[|Download\w+:)'
– Chadwick
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What would cause an algorithm to have O(log n) complexity?
...er dividing n in half i times we'll have a value that is at most 1. The smallest i for which this is guaranteed is roughly log2 n, so if we have an algorithm that divides by 2 until the number gets sufficiently small, then we can say that it terminates in O(log n) steps.
An important detail is tha...
select and update database record with a single queryset
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@learning well dude, it all depends on your scenario. The update method is great for mass updates, but it should set off a warning in your head when you use it that you need to review any signals attached to that object that might also need to be m...
Which commit has this blob?
... scripts take the blob’s SHA1 as the first argument, and after it, optionally, any arguments that git log will understand. E.g. --all to search in all branches instead of just the current one, or -g to search in the reflog, or whatever else you fancy.
Here it is as a shell script – short and sw...
How to programmatically determine the current checked out Git branch [duplicate]
...ions/git-completion.bash does that for bash prompt in __git_ps1. Removing all extras like selecting how to describe detached HEAD situation, i.e. when we are on unnamed branch, it is:
branch_name="$(git symbolic-ref HEAD 2>/dev/null)" ||
branch_name="(unnamed branch)" # detached HEAD
branc...
What is the result of % in Python?
...s second operand (or zero); the absolute value of the result is strictly smaller than the absolute value of the second operand [2].
Taken from http://docs.python.org/reference/expressions.html
Example 1:
6%2 evaluates to 0 because there's no remainder if 6 is divided by 2 ( 3 times ).
Example 2...
libpng warning: iCCP: known incorrect sRGB profile
...geMagick's
convert in.png out.png
To remove the invalid iCCP chunk from all of the PNG files in a folder (directory), you can use mogrify from ImageMagick:
mogrify *.png
This requires that your ImageMagick was built with libpng16. You can easily check it by running:
convert -list format | gre...
How to check Oracle database for long running queries
...ime -- Time since current mode was granted
from
v$locked_object, all_objects, v$lock
where
v$locked_object.object_id = all_objects.object_id AND
v$lock.id1 = all_objects.object_id AND
v$lock.sid = v$locked_object.session_id
order by
session_id, ctime desc, object_name
/
This is a...