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Why does parseInt yield NaN with Array#map?
...of the element.
In this case, you ended up calling parseInt with radix 0, 1 and 2 in turn. The first is the same as not supplying the parameter, so it defaulted based on the input (base 10, in this case). Base 1 is an impossible number base, and 3 is not a valid number in base 2:
parseInt('1', 0...
Drop all duplicate rows across multiple columns in Python Pandas
...t pandas as pd
df = pd.DataFrame({"A":["foo", "foo", "foo", "bar"], "B":[0,1,1,1], "C":["A","A","B","A"]})
df.drop_duplicates(subset=['A', 'C'], keep=False)
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Add column with constant value to pandas dataframe [duplicate]
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21
The reason this puts NaN into a column is because df.index and the Index of your right-hand-side...
Extracting the last n characters from a ruby string
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101
Here you have a one liner, you can put a number greater than the size of the string:
"123".sp...
Why does ++[[]][+[]]+[+[]] return the string “10”?
This is valid and returns the string "10" in JavaScript ( more examples here ):
9 Answers
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How to randomly sort (scramble) an array in Ruby?
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Built in now:
[1,2,3,4].shuffle => [2, 1, 3, 4]
[1,2,3,4].shuffle => [1, 3, 2, 4]
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Accessing the index in 'for' loops?
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edited Sep 17 '16 at 10:13
Peter Mortensen
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rreplace - How to replace the last occurrence of an expression in a string?
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197
>>> def rreplace(s, old, new, occurrence):
... li = s.rsplit(old, occurrence)
... r...
Repeat each row of data.frame the number of times specified in a column
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175
Here's one solution:
df.expanded <- df[rep(row.names(df), df$freq), 1:2]
Result:
va...