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Go Error Handling Techniques [closed]
...ome would disagree for sure, but I would argue that this is the style seen all over the standard libraries in Golang. In other words, Go authors write error handling in this way.
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NSUserDefaults - How to tell if a key exists
I'm working on a small iPhone app, and I am using NSUserDefaults as my data persistence. It only has to keep track of a few things, such as some names and some numbers so I figure I might as well keep it simple.
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How to check if std::map contains a key without doing insert?
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Use my_map.count( key ); it can only return 0 or 1, which is essentially the Boolean result you want.
Alternately my_map.find( key ) != my_map.end() works too.
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Why git can't remember my passphrase under Windows
...msysgit or not.
First solution Assumes Windows, msysgit, and PuTTY.
Install msysgit and PuTTY as instructed.
(Optional) Add PuTTY to your path. (If you do not do this, then any references to PuTTY commands below must be prefixed with the full path to the appropriate executable.)
If you have not d...
Android selector & text color
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Should the selector really reside under res/color folder?
– mr5
Apr 21 '17 at 4:29
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select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
...1、select实现
select的调用过程如下所示：
（1）使用copy_from_user从用户空间拷贝fd_set到内核空间
（2）注册回调函数__pollwait
（3）遍历所有fd，调用其对应的poll方法（对于socket，这个poll方法是sock_poll，sock_poll根据情况会调用到...
Determine if Android app is being used for the first time
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Beware for Android 6.0 (API 23 - Marshmallow) or above auto backup (developer.android.com/guide/topics/data/autobackup.html)is enabled by default. If the users uninstalls and then reinstalls the app the shared preferences will be recovered. So on reinstalls you ca...
How does Google Instant work?
...xactly how the new google instant search works? It seems to just be AJAX calls to the old search, but it's pretty hard to simplify Google that much. Anybody have speculations?
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How to find third or nth maximum salary from salary table?
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Use ROW_NUMBER(if you want a single) or DENSE_RANK(for all related rows):
WITH CTE AS
(
SELECT EmpID, EmpName, EmpSalary,
RN = ROW_NUMBER() OVER (ORDER BY EmpSalary DESC)
FROM dbo.Salary
)
SELECT EmpID, EmpName, EmpSalary
FROM CTE
WHERE RN = @NthRow
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What is Weak Head Normal Form?
... further (i.e. it contains no un-evaluated thunks).
These expressions are all in normal form:
42
(2, "hello")
\x -> (x + 1)
These expressions are not in normal form:
1 + 2 -- we could evaluate this to 3
(\x -> x + 1) 2 -- we could apply the function
"he" ++ "llo" ...