大约有 40,000 项符合查询结果（耗时：0.0650秒） [XML]
Best way to represent a fraction in Java?
...
//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);
...
Why does (1 in [1,0] == True) evaluate to False?
...arison operator chaining here. The expression is translated to
(1 in [1, 0]) and ([1, 0] == True)
which is obviously False.
This also happens for expressions like
a < b < c
which translate to
(a < b) and (b < c)
(without evaluating b twice).
See the Python language documentat...
How do you use NSAttributedString?
...DK 3.2 (or around 3.2) and is available on the iPhone as of iPhone SDK 4.0 beta .
15 Answers
...
Formatting a float to 2 decimal places
...ass the format in to the ToString method, e.g.:
myFloatVariable.ToString("0.00"); //2dp Number
myFloatVariable.ToString("n2"); // 2dp Number
myFloatVariable.ToString("c2"); // 2dp currency
Standard Number Format Strings
...
Gem::LoadError for mysql2 gem, but it's already in Gemfile
... with rails 4.1.5) try using this version of mysql2:
gem 'mysql2', '~> 0.3.18'
Apparently mysql2 isn't still compatible with newer version of rails because rails 4.2.4 is pretty new as the time of answering this question by me 8 September 2015 so use the above line in your Gem file and run:
...
How to reorder data.table columns (without copying)
...ta.table(a = 1:3, b = 3:1, c = runif(3))
x
# a b c
# [1,] 1 3 0.2880365
# [2,] 2 2 0.7785115
# [3,] 3 1 0.3297416
setcolorder(x, c("c", "b", "a"))
x
# c b a
# [1,] 0.2880365 3 1
# [2,] 0.7785115 2 2
# [3,] 0.3297416 1 3
From ?setcolorder:
In data.table parlance, all s...
Given an array of numbers, return array of products of all other numbers (no division)
...
260
An explanation of polygenelubricants method is:
The trick is to construct the arrays (in the c...
Path to Powershell.exe (v 2.0)
Where is the Powershell (version 2.0) located? What is the path to Powershell.exe? I have Windows Server 2008 and Powershell installed. When I look at this folder:
...
Label points in geom_point
...our="green", label=Name))+
geom_point() +geom_text(aes(label=Name),hjust=0, vjust=0)
EDIT: Label only values above a certain threshold:
ggplot(nba, aes(x= MIN, y= PTS, colour="green", label=Name))+
geom_point() +
geom_text(aes(label=ifelse(PTS>24,as.character(Name),'')),hjust=0,vjust...
Assign pandas dataframe column dtypes
...
Since 0.17, you have to use the explicit conversions:
pd.to_datetime, pd.to_timedelta and pd.to_numeric
(As mentioned below, no more "magic", convert_objects has been deprecated in 0.17)
df = pd.DataFrame({'x': {0: 'a', 1: 'b'}...