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Best way to represent a fraction in Java?
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//only numerator should be negative.
if(denominator.signum() < 0)
{
numerator = numerator.negate();
denominator = denominator.negate();
}
//create a reduced fraction
BigInteger gcd = numerator.gcd(denominator);
this.numerator = numerator.divide(gcd);
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Equivalent of String.format in jQuery
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20 Answers
20
Active
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Pandas dataframe get first row of each group
...column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 second
4 5 first
5 6 first
6 7 fourth
To get n first records, you can use head():
>>> df.groupby('id').head(2).reset_index(drop=True)
id value
0 ...
Why does the indexing start with zero in 'C'?
...f the array is exactly contained in the memory location that array refers (0 elements away), so it should be denoted as array[0].
For more info:
http://developeronline.blogspot.com/2008/04/why-array-index-should-start-from-0.html
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Memcached下一站：HandlerSocket！ - 更多技术 - 清泛网 - 专注C/C++及内核技术
...期的数据，就会造成数据不一致。这在强调即时性的Web2.0时代，不可取。
Memcached崩溃后的雪崩效应：作为缓存的Memcached一旦崩溃，MySQL很可能在短时间内承受高负载而宕机。据说前段时间新浪微博就遭遇了这样的问题。
注：...
How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops
...ns:
- Range.
E.g. a-z matches an lower case letters from a to z
E.g. 0-5 matches any number from 0 to 5
[] Match exactly one of the objects inside these brackets.
E.g. [a] matches the letter a
E.g. [abc] matches a single letter which can be a, b or c
E.g. [a-z] matches any single lower cas...
Double vs. BigDecimal?
...s a certain precision. Working with doubles of various magnitudes (say d1=1000.0 and d2=0.001) could result in the 0.001 being dropped alltogether when summing as the difference in magnitude is so large. With BigDecimal this would not happen.
The disadvantage of BigDecimal is that it's slower, and ...
Initialising an array of fixed size in python [duplicate]
...sked.
– samplebias
Aug 25 '14 at 21:08
3
This meets the requirements of the question because you ...
Bitwise operation and usage
...bit at a time.
AND is 1 only if both of its inputs are 1, otherwise it's 0.
OR is 1 if one or both of its inputs are 1, otherwise it's 0.
XOR is 1 only if exactly one of its inputs are 1, otherwise it's 0.
NOT is 1 only if its input is 0, otherwise it's 0.
These can often be best shown as truth ...
Check if all elements in a list are identical
..., for Python 2.7 and (only s1, s4, s7, s9 should return True)
s1 = [1] * 5000
s2 = [1] * 4999 + [2]
s3 = [2] + [1]*4999
s4 = [set([9])] * 5000
s5 = [set([9])] * 4999 + [set([10])]
s6 = [set([10])] + [set([9])] * 4999
s7 = [1,1]
s8 = [1,2]
s9 = []
we get
| checkEqual1 | checkEqual2 | checkE...