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Linux下安装项目管理工具Redmine - 开源 & Github - 清泛网 - 专注C/C++及内核技术
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# wget http://rubyforge.org/frs/download.php/60718/rubygems-1.3.5.tgz
# tar zxvf rubygems-1.3.5.tgz
# cd rubygems-1.3.5
# ruby setup.rb
3、Rake安装
# gem install rake //直接使用gem命令安装rake.
//也可以下载安装地址:http://rubyforge.org/...
Calculate difference in keys contained in two Python dictionaries
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234
You can use set operations on the keys:
diff = set(dictb.keys()) - set(dicta.keys())
Here is...
Determine the data types of a data frame's columns
...o use ?str(). To explore some examples, let's make some data:
set.seed(3221) # this makes the example exactly reproducible
my.data <- data.frame(y=rnorm(5),
x1=c(1:5),
x2=c(TRUE, TRUE, FALSE, FALSE, FALSE),
X3=letters[1:5])
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PHP Pass by reference in foreach [duplicate]
...ee');
foreach ($a as &$v) {
}
foreach ($a as $v) {
echo $v.'-'.$a[3].PHP_EOL;
}
As you can see, the last array item takes the current loop value: 'zero', 'one', 'two', and then it's just 'two'... : )
share
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Regular expression that matches valid IPv6 addresses
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30 Answers
30
Active
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Converting int to bytes in Python 3
I was trying to build this bytes object in Python 3:
13 Answers
13
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“Cloning” row or column vectors
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83
Here's an elegant, Pythonic way to do it:
>>> array([[1,2,3],]*3)
array([[1, 2, 3],
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What are the differences between json and simplejson Python modules?
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13 Answers
13
Active
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How can I sort a dictionary by key?
What would be a nice way to go from {2:3, 1:89, 4:5, 3:0} to {1:89, 2:3, 3:0, 4:5} ?
I checked some posts but they all use the "sorted" operator that returns tuples.
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For each row return the column name of the largest value
...amples using sample reproducible):
DF <- data.frame(V1=c(2,8,1),V2=c(7,3,5),V3=c(9,6,4))
colnames(DF)[apply(DF,1,which.max)]
[1] "V3" "V1" "V2"
A faster solution than using apply might be max.col:
colnames(DF)[max.col(DF,ties.method="first")]
#[1] "V3" "V1" "V2"
...where ties.method can be...
