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Using numpy to build an array of all combinations of two arrays
... faster implementation:
@pv's solution
In [113]:
%timeit cartesian(([1, 2, 3], [4, 5], [6, 7]))
10000 loops, best of 3: 135 µs per loop
In [114]:
cartesian(([1, 2, 3], [4, 5], [6, 7]))
Out[114]:
array([[1, 4, 6],
[1, 4, 7],
[1, 5, 6],
[1, 5, 7],
[2, 4, 6],
[2...
Pandas index column title or name
...0]:
Column 1
foo
Apples 1
Oranges 2
Puppies 3
Ducks 4
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How to select rows from a DataFrame based on column values?
... three'.split(),
'C': np.arange(8), 'D': np.arange(8) * 2})
print(df)
# A B C D
# 0 foo one 0 0
# 1 bar one 1 2
# 2 foo two 2 4
# 3 bar three 3 6
# 4 foo two 4 8
# 5 bar two 5 10
# 6 foo one 6 12
# 7 foo three 7 14
pri...
What are the mathematical/computational principles behind this game?
...into the soup and you have the question:
Can we have a geometry with just 2 points? With 3 points? With 4? With 7?
There are still open questions regarding this problem but we do know this:
If there are geometries with Q points, then Q = n^2 + n + 1 and n is called the order of the geometry.
The...
Can dplyr package be used for conditional mutating?
...
220
Use ifelse
df %>%
mutate(g = ifelse(a == 2 | a == 5 | a == 7 | (a == 1 & b == 4), 2,
...
get list from pandas dataframe column
...st it with list(x).
import pandas as pd
data_dict = {'one': pd.Series([1, 2, 3], index=['a', 'b', 'c']),
'two': pd.Series([1, 2, 3, 4], index=['a', 'b', 'c', 'd'])}
df = pd.DataFrame(data_dict)
print(f"DataFrame:\n{df}\n")
print(f"column types:\n{df.dtypes}")
col_one_list = df['one'...
Why does Math.round(0.49999999999999994) return 1?
....1 This is a specification bug, for precisely this one pathological case.2 Java 7 no longer mandates this broken implementation.3
The problem
0.5+0.49999999999999994 is exactly 1 in double precision:
static void print(double d) {
System.out.printf("%016x\n", Double.doubleToLongBits(d));
}
...
For each row return the column name of the largest value
...d() to make examples 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...
Is it possible to install another version of Python to Virtualenv?
I have a shared account in a web-hosting that has Python 2.4 installed, but my code is not compatible with 2.4. Is it possible to install Python 2.6 directly to Virtualenv?
...
Logical operators for boolean indexing in Pandas
...
219
When you say
(a['x']==1) and (a['y']==10)
You are implicitly asking Python to convert (a['x...