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How to count the frequency of the elements in an unordered list?
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numpy: most efficient frequency counts for unique values in an array
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16 Answers
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Index all *except* one item in python
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For a list, you could use a list comp. For example, to make b a copy of a without the 3rd ele...
How to initialize an array in one step using Ruby?
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You can use an array literal:
array = [ '1', '2', '3' ]
You can also use a range:
array = ...
Drop rows with all zeros in pandas data frame
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12 Answers
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How exactly does tail recursion work?
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The compiler is simply able to transform this
int fac_times (int n, int acc) {
if (n == 0...
How can I check if a string represents an int, without using try/except?
... any way to tell whether a string represents an integer (e.g., '3' , '-17' but not '3.14' or 'asfasfas' ) Without using a try/except mechanism?
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How do I compare version numbers in Python?
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10 Answers
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Determine the data types of a data frame's columns
...se ?str(). To explore some examples, let's make some data:
set.seed(3221) # this makes the example exactly reproducible
my.data <- data.frame(y=rnorm(5),
x1=c(1:5),
x2=c(TRUE, TRUE, FALSE, FALSE, FALSE),
X3=letters[1:5])
@...
Expand a random range from 1–5 to 1–7
Given a function which produces a random integer in the range 1 to 5, write a function which produces a random integer in the range 1 to 7.
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