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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...
Summarizing multiple columns with dplyr? [duplicate]
...df %>% group_by(grp) %>% summarise_all(list(mean))
#> # A tibble: 3 x 5
#> grp a b c d
#> <int> <dbl> <dbl> <dbl> <dbl>
#> 1 1 3.08 2.98 2.98 2.91
#> 2 2 3.03 3.04 2.97 2.87
#> 3 3 2.85 2.95 2.95 3.06...
Applying a function to every row of a table using dplyr?
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edited Aug 6 '19 at 3:20
answered Jul 14 '14 at 0:20
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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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Fastest way to list all primes below N
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35 Answers
35
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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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How to generate all permutations of a list?
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33 Answers
33
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LINGO使用指南 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...如下的LP问题：
在模型窗口中输入如下代码：
min=2*x1+3*x2;
x1+x2>=350;
x1>=100;
2*x1+x2<=600;
然后点击工具条上的按钮 即可。
例1.2 使用LINGO软件计算6个发点8个收点的最小费用运输问题。产销单位运价如下表。
销地
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Split a vector into chunks in R
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326
A one-liner splitting d into chunks of size 20:
split(d, ceiling(seq_along(d)/20))
More det...
What's the difference between tilde(~) and caret(^) in package.json?
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4053
See the NPM docs and semver docs:
~version “Approximately equivalent to version”, will upda...