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Float vs Decimal in ActiveRecord
... a Float. It's like a scientific notation for binary (something like +1.43*10^2). Because of that, it is impossible to store fractions and decimals in Float exactly.
That's why there is a Decimal format. If you do this:
irb:001:0> "%.47f" % (1.0/10)
=> "0.10000000000000000555111512312578270...
Ruby sleep or delay less than a second?
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answered Mar 30 '10 at 5:31
Georg SchöllyGeorg Schölly
113k4646 gold badges197197 silver badges254254 bronze badges
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Shuffle two list at once with same order
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– Jaroslav Klimčík
Apr 25 '14 at 10:15
4
(noob question) - what does the * mean?
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How to find which rspec test is taking so long
...profile flag or add --profile to your .rspec file. This will track the top 10 slowest examples.
For RSpec 1, you can use --format o with spec command. It shows a text-based progress bar with profiling of 10 slowest examples. For more details see this.
rspec --profile -- path/to/file/spec.rb
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Instance variables vs. class variables in Python
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answered Apr 26 '10 at 15:16
Alex MartelliAlex Martelli
724k148148 gold badges11261126 silver badges13241324 bronze badges
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How to declare constant map
... a pseudo-constant), you can do:
var romanNumeralDict = map[int]string{
1000: "M",
900 : "CM",
500 : "D",
400 : "CD",
100 : "C",
90 : "XC",
50 : "L",
40 : "XL",
10 : "X",
9 : "IX",
5 : "V",
4 : "IV",
1 : "I",
}
Inside a func you can declare it like:
romanNum...
Unique combination of all elements from two (or more) vectors
... GHI 2012-05-02
7 ABC 2012-05-03
8 DEF 2012-05-03
9 GHI 2012-05-03
10 ABC 2012-05-04
11 DEF 2012-05-04
12 GHI 2012-05-04
13 ABC 2012-05-05
14 DEF 2012-05-05
15 GHI 2012-05-05
If the resulting order isn't what you want, you can sort afterwards. If you name the arguments to expand.grid...
Remove first 4 characters of a string with PHP
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edited Nov 26 '10 at 15:23
answered Nov 26 '10 at 15:16
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JSON.parse vs. eval()
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110
You are more vulnerable to attacks if using eval: JSON is a subset of Javascript and json.pars...
java: run a function after a specific number of seconds
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