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How do you match only valid roman numerals with a regular expression?
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330
You can use the following regex for this:
^M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3...
How do I convert a TimeSpan to a formatted string? [duplicate]
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edited Aug 16 '09 at 17:51
answered May 8 '09 at 22:22
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Remove outline from select box in FF
...he color of the dotted border. So say if you do...
select {
color: rgba(0,0,0,0);
}
Firefox will render the dotted border transparent. But of course your text will be transparent too! So we must somehow display the text. text-shadow comes to the rescue:
select {
color: rgba(0,0,0,0);
text-...
Why is address zero used for the null pointer?
...s a pointer with the value zero if it can't get me memory; I use if (p != 0) all the time to make sure passed pointers are valid, etc.
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pandas: filter rows of DataFrame with operator chaining
... boolean index.
In [96]: df
Out[96]:
A B C D
a 1 4 9 1
b 4 5 0 2
c 5 5 1 0
d 1 3 9 6
In [99]: df[(df.A == 1) & (df.D == 6)]
Out[99]:
A B C D
d 1 3 9 6
If you want to chain methods, you can add your own mask method and use that one.
In [90]: def mask(df, key, ...
Sample random rows in dataframe
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460
First make some data:
> df = data.frame(matrix(rnorm(20), nrow=10))
> df
X1 ...
Find XOR of all numbers in a given range
...ven a large range [a,b] where 'a' and 'b' can be typically between 1 and 4,000,000,000 inclusive. You have to find out the XOR of all the numbers in the given range.
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How to grant remote access to MySQL for a whole subnet?
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edited Nov 14 '17 at 20:33
answered Jul 31 '12 at 15:01
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Why do Lua arrays(tables) start at 1 instead of 0?
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Although I too found them weird at the beginning, I have learned to love 0-based arrays. But I get by OK with Lua's 1-based arrays, especially by
using Lua's generic for loop and the ipairs operator—I can usually avoid worrying about just how arrays are indexed.
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What is Bit Masking?
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250
A mask defines which bits you want to keep, and which bits you want to clear.
Masking is the ac...