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cartesian product in pandas
...rom pandas import DataFrame, merge
df1 = DataFrame({'key':[1,1], 'col1':[1,2],'col2':[3,4]})
df2 = DataFrame({'key':[1,1], 'col3':[5,6]})
merge(df1, df2,on='key')[['col1', 'col2', 'col3']]
Output:
col1 col2 col3
0 1 3 5
1 1 3 6
2 2 4 5
3 2 4 6...
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...
Is there a reason that we cannot iterate on “reverse Range” in ruby?
...
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__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...
What is the use of the ArraySegment class?
...l array, get the first item, and so on:
var array = new byte[] { 5, 8, 9, 20, 70, 44, 2, 4 };
array.Dump();
var segment = new ArraySegment<byte>(array, 2, 3);
segment.Dump(); // output: 9, 20, 70
segment.Reverse().Dump(); // output 70, 20, 9
segment.Any(s => s == 99).Dump(); // output fals...
Round to 5 (or other number) in Python
...
312
I don't know of a standard function in Python, but this works for me:
Python 2
def myround(x, ...
What exactly do “u” and “r” string flags do, and what are raw string literals?
...
702
There's not really any "raw string"; there are raw string literals, which are exactly the string...
CALayer with transparent hole in it
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219
I was able to solve this with Jon Steinmetz suggestion. If any one cares, here's the final sol...