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Detect if value is number in MySQL
... FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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Divide a number by 3 without using *, /, +, -, % operators
... because:
n = 4 * a + b
n / 3 = a + (a + b) / 3
So sum += a, n = a + b, and iterate
When a == 0 (n < 4), sum += floor(n / 3); i.e. 1, if n == 3, else 0
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“static const” vs “#define” vs “enum”
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It depends on what you need the value for. You (and everyone else so far) omitted the third alternative:
static const int var = 5;
#define var 5
enum { var = 5 };
Ignoring issues about the choice of name, then:
If you need to pass a pointer around, you must use (1).
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@Media min-width & max-width
...ult CSS for the older browsers, as older browsers including i.e. 5.5, 6, 7 and 8. Can't read @media. When I use @media I use it like this:
<style type="text/css">
/* default styles here for older browsers.
I tend to go for a 600px - 960px width max but using percentages
*/
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Sort array of objects by string property value
...are function body: return a.value - b.value; (ASC)
– Andre Figueiredo
Jan 8 '14 at 12:06
23
@Cerb...
Ruby optional parameters
...his method: e.g. If you're trying to make the default value for scope true and you pass in false, scope ||= true won't work. It evaluates the same as nil and will set it to true
– Joshua Pinter
Nov 10 '11 at 5:32
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Git copy file preserving history [duplicate]
... confusing question in Git.
Lets say, I have a file dir1/A.txt committed and git preserves a history of commits
7 Answers...
Capitalize only first character of string and leave others alone? (Rails)
I'm trying to get Rails to capitalize the first character of a string, and leave all the others the way they are. I'm running into a problem where "i'm from New York" gets turned into "I'm from new york."
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adding noise to a signal in python
I want to add some random noise to some 100 bin signal that I am simulating in Python - to make it more realistic.
7 Answer...
Efficient Algorithm for Bit Reversal (from MSB->LSB to LSB->MSB) in C
... trade off memory for speed (assuming your L1 Data Cache is large enough), and reverse 16 bits at a time with a 64K-entry lookup table.
Others
Simple
unsigned int v; // input bits to be reversed
unsigned int r = v & 1; // r will be reversed bits of v; first get LSB of v
int s = sizeof(v...