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Can inner classes access private variables?
... {
i.func();
}
private:
static const char* const MYCONST;
Inner i;
int var;
};
const char* const Outer::MYCONST = "myconst";
int main()
{
Outer o1;
Outer o2(o1);
o1.func();
o2.func();
}
...
Find the max of two or more columns with pandas
...DataFrame(np.random.randn(5, 1000))
perfplot.show(
setup=lambda n: pd.concat([df_] * n, ignore_index=True),
kernels=[
lambda df: df.assign(new=df.max(axis=1)),
lambda df: df.assign(new=df.values.max(1)),
lambda df: df.assign(new=np.nanmax(df.values, axis=1)),
...
MySQL - ORDER BY values within IN()
...
just use
order by INSTR( ',B,C,D,A,' , concat(',' , `field`, ',' ) )
avoid the situation like
INSTR('1,2,3,11' ,`field`)
will end with unordered result row : 1 and 11 alternant
s...
What is a reasonable length limit on person “Name” fields?
...put their information, including name. I gave the name field a limit of 50 characters to coincide with my database table where the field is varchar(50), but then I started to wonder.
...
C++: What is the size of an object of an empty class?
...aligned on a word boundary (such as an integer). For example, if you place char x; int y; inside the class, my GCC clocks it at eight bytes (since the second int must be aligned in that implementation).
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...
Format date and time in a Windows batch script
...ces with zeros.
Short explanation of how substrings work:
%VARIABLE:~num_chars_to_skip,num_chars_to_keep%
So to get just the year from a date like "29.03.2018" use:
%DATE:~6,4%
^-----skip 6 characters
^---keep 4 characters
...
How exactly does the callstack work?
... pointer arithmetic.
Example
#include <iostream>
int main()
{
char c = std::cin.get();
std::cout << c;
}
gcc.godbolt.org gives us
main:
pushq %rbp
movq %rsp, %rbp
subq $16, %rsp
movl std::cin, %edi
call std::basic_istream<char, std::cha...
Why don't Java's +=, -=, *=, /= compound assignment operators require casting?
...57
or
byte b = 100;
b /= 2.5;
System.out.println(b); // prints 40
or
char ch = '0';
ch *= 1.1;
System.out.println(ch); // prints '4'
or
char ch = 'A';
ch *= 1.5;
System.out.println(ch); // prints 'a'
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...
CSS hexadecimal RGBA?
... = 'rgba(' + matches.slice(1).map(function(m) { return parseInt(m, 16); }).concat(a) + ')';
– PointedEars
Nov 27 '11 at 14:47
...
What is the difference between a mutable and immutable string in C#?
...is mutable)
so if you have to alter a string many times, such as multiple concatenations, then use StringBuilder.
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