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How to return a part of an array in Ruby?
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Yes, Ruby has very similar array-slicing syntax to Python. Here is the ri documentation for th...
What does -1 mean in numpy reshape?
...atrix can be reshaped into a vector using reshape function with parameter -1. But I don't know what -1 means here.
9 Answer...
Frequency table for a single variable
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153
Maybe .value_counts()?
>>> import pandas
>>> my_series = pandas.Series([1,2...
How to compare two strings in dot separated version format in Bash?
...ny way to compare such strings on bash, e.g.: 2.4.5 and 2.8 and 2.4.5.1 ?
29 Answers
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What is the best regular expression to check if a string is a valid URL?
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Apply a function to every row of a matrix or a data frame
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182
You simply use the apply() function:
R> M <- matrix(1:6, nrow=3, byrow=TRUE)
R> M
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How to get row from R data.frame
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x[r,]
where r is the row you're interested in. Try this, for example:
#Add your data
x <...
How to drop columns by name in a data frame
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Reorder levels of a factor without changing order of values
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Use the levels argument of factor:
df <- data.frame(f = 1:4, g = letters[1:4])
df
# f g
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