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How to check if a variable is set in Bash?
...ar+x} is a parameter expansion which evaluates to nothing if var is unset, and substitutes the string x otherwise.
Quotes Digression
Quotes can be omitted (so we can say ${var+x} instead of "${var+x}") because this syntax & usage guarantees this will only expand to something that does not requ...
Jump to editor shortcut in Intellij IDEA
...how hard I had to look for that information :)
– Alexander Torstling
May 3 '12 at 6:43
33
Hi! Tha...
What is the official “preferred” way to install pip and virtualenv systemwide?
...
If you can install the latest Python (2.7.9 and up) Pip is now bundled with it.
See: https://docs.python.org/2.7//installing/index.html
If not :
Update (from the release notes):
Beginning with v1.5.1, pip does not require setuptools prior to running get-pip.py. Ad...
Most efficient way to increment a Map value in Java
...ood answers to this question--thanks folks--so I decided to run some tests and figure out which method is actually fastest. The five methods I tested are these:
the "ContainsKey" method that I presented in the question
the "TestForNull" method suggested by Aleksandar Dimitrov
the "AtomicLong" meth...
Error when trying vagrant up
I'm using Vagrant for my environment and I've got a little issue:
23 Answers
23
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MySQL复制的概述、安装、故障、技巧、工具 - 数据库(内核) - 清泛网 - 专注...
...内容：
High Performance MySQL: Optimization, Backups, Replication, and More
MySQL High Availability: Tools for Building Robust Data Centers
希望我的总结能让大家少走一些弯路。
MySQL复制
Declaration suffix for decimal type
...mal literal in code, I have seen that there exists the m-suffix (where m stands for money). Is this appropriate for any decimals or is there a more general assignment (d stands for double, that is for sure not the right thing although a direct conversion is supported).
...
How to change package name of an Android Application
My keystore is corrupt, therefore the Android Market is requiring me to rename the app and resubmit it. However, whenever I go to edit the package names in Manifest and throughout the files, it gives me tons of errors.
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Best practices for overriding isEqual: and hash
...ive you do
result = prime * result + var
For objects you use 0 for nil and otherwise their hashcode.
result = prime * result + [var hash];
For booleans you use two different values
result = prime * result + ((var)?1231:1237);
Explanation and Attribution
This is not tcurdt's work, and ...
How do I properly clean up Excel interop objects?
I'm using the Excel interop in C# ( ApplicationClass ) and have placed the following code in my finally clause:
41 Answers
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