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Formula to determine brightness of RGB color
... → sqrt( 0.299*R^2 + 0.587*G^2 + 0.114*B^2 ) (thanks to @MatthewHerbst) [3]
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Could not load file or assembly 'Newtonsoft.Json, Version=4.5.0.0, Culture=neutral, PublicKeyToken=3
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edited May 19 '16 at 12:31
s_a
16322 silver badges44 bronze badges
answered Apr 30 '14 at 7:00
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Pandas groupby: How to get a union of strings
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In [5]: df
Out[5]:
A B C
0 1 0.749065 This
1 2 0.301084 is
2 3 0.463468 a
3 4 0.643961 random
4 1 0.866521 string
5 2 0.120737 !
In [6]: df.dtypes
Out[6]:
A int64
B float64
C object
dtype: object
When you apply your own function, t...
How to check if a string is a valid hex color representation?
... -> match end
i -> ignore case
If you need support for 3-character HEX codes, use the following:
/^#([0-9A-F]{3}){1,2}$/i.test('#ABC')
The only difference here is that
[0-9A-F]{6}
is replaced with
([0-9A-F]{3}){1,2}
This means that instead of matching exactly 6 charact...
Getting the array length of a 2D array in Java
...tring[] args) {
int[][] foo = new int[][] {
new int[] { 1, 2, 3 },
new int[] { 1, 2, 3, 4},
};
System.out.println(foo.length); //2
System.out.println(foo[0].length); //3
System.out.println(foo[1].length); //4
}
Column lengths differ per row. If you're backing...
Selecting data frame rows based on partial string match in a column
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3 Answers
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Need a simple explanation of the inject method
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edited Apr 2 '09 at 16:37
answered Apr 2 '09 at 16:31
Dr...
Avoid trailing zeroes in printf()
...tf format specifiers. The closest you could get would be:
printf("%.6g", 359.013); // 359.013
printf("%.6g", 359.01); // 359.01
but the ".6" is the total numeric width so
printf("%.6g", 3.01357); // 3.01357
breaks it.
What you can do is to sprintf("%.20g") the number to a string buffer then...
Convert list of dictionaries to a pandas DataFrame
...24
cs95
231k6060 gold badges390390 silver badges455455 bronze badges
answered Dec 17 '13 at 15:35
jorisjoris
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Why is address zero used for the null pointer?
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edited May 3 '10 at 17:44
answered May 3 '10 at 17:22
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