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What is the difference between JOIN and UNION?
...mpletely different operations. Trivial example of UNION:
mysql> SELECT 23 AS bah
-> UNION
-> SELECT 45 AS bah;
+-----+
| bah |
+-----+
| 23 |
| 45 |
+-----+
2 rows in set (0.00 sec)
similary trivial example of JOIN:
mysql> SELECT * FROM
-> (SELECT 23 AS bah) AS fo...
How to initialize a dict with keys from a list and empty value in Python?
...
dict.fromkeys([1, 2, 3, 4])
This is actually a classmethod, so it works for dict-subclasses (like collections.defaultdict) as well. The optional second argument specifies the value to use for the keys (defaults to None.)
...
Closure in Java 7 [closed]
...e pioneers introducing closures in Java. His post on closures from January 28, 2007 is named A Definition of Closures On his blog there is lots of information to get you started as well as videos. An here is an excellent Google talk - Advanced Topics In Programming Languages - Closures For Java with...
do { … } while (0) — what is it good for? [duplicate]
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edited Nov 3 '08 at 9:24
answered Nov 2 '08 at 21:40
Gr...
Grep for literal strings
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answered Jul 14 '10 at 2:08
Scott StaffordScott Stafford
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How to print a query string with parameter values when using Hibernate
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edited Apr 25 '17 at 13:53
Abdull
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Pandas DataFrame Groupby two columns and get counts
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126
Followed by @Andy's answer, you can do following to solve your second question:
In [56]: df.gr...
How to remove all leading zeroes in a string
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answered Feb 23 '11 at 23:36
lonesomedaylonesomeday
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What are differences between AssemblyVersion, AssemblyFileVersion and AssemblyInformationalVersion?
...r strictly then this means you only update when the major changes, so 1.0, 2.0, 3.0, etc.
AssemblyFileVersion
Used for deployment. You can increase this number for every deployment. It is used by setup programs. Use it to mark assemblies that have the same AssemblyVersion, but are generated from d...
__attribute__ - C/C++ - 清泛网 - 专注C/C++及内核技术
...一个带有可变参数的函数，其功能类似于printf：
//m=1；n=2
extern void myprint(const char *format,...) __attribute__((format(printf,1,2)));
//m=2；n=3
extern void myprint(int l，const char *format,...)
__attribute__((format(printf,2,3)));
需要特别注意的是，如果my...