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If vs. Switch Speed
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answered Jan 14 '09 at 23:16
Konrad RudolphKonrad Rudolph
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Find unique rows in numpy.array
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As of NumPy 1.13, one can simply choose the axis for selection of unique values in any N-dim array. To get unique rows, one can do:
unique_rows = np.unique(original_array, axis=0)
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Drop rows with all zeros in pandas data frame
...0,1,0,1]})
> df = df[(df.T != 0).any()]
> df
a b
1 0 1
2 1 0
3 1 1
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Regular expression for matching latitude/longitude coordinates?
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Miha_x64
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answered Aug 19 '10 at 3:38
Eric CEric C
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How can I obtain the element-wise logical NOT of a pandas Series?
... True, False, True])
In [8]: ~s
Out[8]:
0 False
1 False
2 True
3 False
dtype: bool
Using Python2.7, NumPy 1.8.0, Pandas 0.13.1:
In [119]: s = pd.Series([True, True, False, True]*10000)
In [10]: %timeit np.invert(s)
10000 loops, best of 3: 91.8 µs per loop
In [11]: %timeit ~s
10...
Dynamically select data frame columns using $ and a character value
... a reproducible example below:
# set seed for reproducibility
set.seed(123)
df <- data.frame( col1 = sample(5,10,repl=T) , col2 = sample(5,10,repl=T) , col3 = sample(5,10,repl=T) )
# We want to sort by 'col3' then by 'col1'
sort_list <- c("col3","col1")
# Use 'do.call' to call order. Sec...
Replace all 0 values to NA
...me space for it. E.g.,
data.frame(x = c(1, NA, 2))
# x
# 1 1
# 2 NA
# 3 2
Also, the data frame structure requires all the columns to have the same number of elements so that there can be no "holes" (i.e., NULL values).
Now you could replace zeroes by NULL in a data frame in the sense of com...
Remove last item from array
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edited Aug 3 at 10:48
CroMagnon
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a...
Is it worth using Python's re.compile?
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TriptychTriptych
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Divide a number by 3 without using *, /, +, -, % operators
How would you divide a number by 3 without using * , / , + , - , % , operators?
48 Answers
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