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What does -1 mean in numpy reshape?
...inal shape'
numpy allow us to give one of new shape parameter as -1 (eg: (2,-1) or (-1,3) but not (-1, -1)). It simply means that it is an unknown dimension and we want numpy to figure it out. And numpy will figure this by looking at the 'length of the array and remaining dimensions' and making su...
MySQL: What's the difference between float and double?
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edited Jan 29 '10 at 9:12
answered Jan 29 '10 at 9:04
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Converting integer to binary in python
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TrebledJ
6,23555 gold badges1919 silver badges4141 bronze badges
answered May 2 '12 at 9:32
eumiroeumiro
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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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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 ...
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...
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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How can I obtain the element-wise logical NOT of a pandas Series?
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274
To invert a boolean Series, use ~s:
In [7]: s = pd.Series([True, True, False, True])
In [8]:...
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
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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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