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Sample random rows in dataframe
...
First make some data:
> df = data.frame(matrix(rnorm(20), nrow=10))
> df
X1 X2
1 0.7091409 -1.4061361
2 -1.1334614 -0.1973846
3 2.3343391 -0.4385071
4 -0.9040278 -0.6593677
5 0.4180331 -1.2592415
6 0.7572246 -0.5463655
7 -0.8996483 0.4231117
8 ...
How do write IF ELSE statement in a MySQL query
...ably want to use a CASE expression.
They look like this:
SELECT col1, col2, (case when (action = 2 and state = 0)
THEN
1
ELSE
0
END)
as state from tbl1;
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Converting integer to binary in python
...
TrebledJ
6,23555 gold badges1919 silver badges4141 bronze badges
answered May 2 '12 at 9:32
eumiroeumiro
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how do I insert a column at a specific column index in pandas?
...e beginning
df.insert(loc, column, value)
df = pd.DataFrame({'B': [1, 2, 3], 'C': [4, 5, 6]})
df
Out:
B C
0 1 4
1 2 5
2 3 6
idx = 0
new_col = [7, 8, 9] # can be a list, a Series, an array or a scalar
df.insert(loc=idx, column='A', value=new_col)
df
Out:
A B C
0 7 1 4
...
Converting a list to a set changes element order
...the list, you can do this with a list comprehension:
>>> a = [1, 2, 20, 6, 210]
>>> b = set([6, 20, 1])
>>> [x for x in a if x not in b]
[2, 210]
If you need a data structure that supports both fast membership tests and preservation of insertion order, you can use the k...
How can I obtain the element-wise logical NOT of a pandas Series?
...
274
To invert a boolean Series, use ~s:
In [7]: s = pd.Series([True, True, False, True])
In [8]:...
How can I get the intersection, union, and subset of arrays in Ruby?
...union
def |(other)
@set | other.set
end
end
x = MultiSet.new([1,1,2,2,3,4,5,6])
y = MultiSet.new([1,3,5,6])
p x - y # [2,2,4]
p x & y # [1,3,5,6]
p x | y # [1,2,3,4,5,6]
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Subscripts in plots in R
...to write subscripts in the title or the subtitle in R.
How can I write v 1,2 with 1,2 as subscripts?
6 Answers
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JdbcTemplate queryForInt/Long is deprecated in Spring 3.2.2. What should it be replaced by?
...ueryforInt/queryforLong methods in JdbcTemplate are deprecated in Spring 3.2. I can't find out why or what is considered the best practice to replace existing code using these methods.
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Obfuscated C Code Contest 2006. Please explain sykes2.c
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1824
Let's de-obfuscate it.
Indenting:
main(_) {
_^448 && main(-~_);
putchar(--_%6...