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Batch renaming files with Bash
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192
You could use bash's parameter expansion feature
for i in ./*.pkg ; do mv "$i" "${i/-[0-9.]*.pk...
How to filter Pandas dataframe using 'in' and 'not in' like in SQL
...le:
import pandas as pd
>>> df
country
0 US
1 UK
2 Germany
3 China
>>> countries_to_keep
['UK', 'China']
>>> df.country.isin(countries_to_keep)
0 False
1 True
2 False
3 True
Name: country, dtype: bool
>>> df[df.country.isin(cou...
How to limit depth for recursive file list?
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edited Dec 22 '10 at 13:39
answered Dec 22 '10 at 13:31
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Why can't I use a list as a dict key in python?
...uality. Many would - understandably - expect that you can use any list [1, 2] to get the same key, where you'd have to keep around exactly the same list object. But lookup by value breaks as soon as a list used as key is modified, and for lookup by identity requires you to keep around exactly the sa...
Combine two or more columns in a dataframe into a new column with a new name
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132
Use paste.
df$x <- paste(df$n,df$s)
df
# n s b x
# 1 2 aa TRUE 2 aa
# 2 3 bb F...
Rank items in an array using Python/NumPy, without sorting array twice
...se slicing on the left-hand side in the last step:
array = numpy.array([4,2,7,1])
temp = array.argsort()
ranks = numpy.empty_like(temp)
ranks[temp] = numpy.arange(len(array))
This avoids sorting twice by inverting the permutation in the last step.
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What does |= (ior) do in Python?
...e examples below.
Sets
For example, the union of two assigned sets s1 and s2 share the following equivalent expressions:
>>> s1 = s1 | s12 # 1
>>> s1 |= s2 # 2
>>> s1.__ior__(s2) ...
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]:...
Using multiple let-as within a if-statement in Swift
...itudeDouble is non-optional in here and importantThing is true
}
Swift 1.2:
Apple may have read your question, because your hoped-for code compiles properly in Swift 1.2 (in beta today):
if let latitudeDouble = latitude as? Double, longitudeDouble = longitude as? Double {
// do stuff here
}
...
Datatype for storing ip address in SQL Server
... IPv4 is binary(4), since that is what it actually is (no, not even an INT32/INT(4), the numeric textual form that we all know and love (255.255.255.255) being just the display conversion of its binary content).
If you do it this way, you will want functions to convert to and from the textual-displ...