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Reverse a string in Python
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How about:
>>> 'hello world'[::-1]
'dlrow olleh'
This is extended slice syntax. It works by doing [begin:end:step] - by leaving begin and end off and specifying a step of -1, it reverses a string.
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Can hash tables really be O(1)?
It seems to be common knowledge that hash tables can achieve O(1), but that has never made sense to me. Can someone please explain it? Here are two situations that come to mind:
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Best way to find if an item is in a JavaScript array? [duplicate]
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As of ECMAScript 2016 you can use includes()
arr.includes(obj);
If you want to support IE or other older browsers:
function include(arr,obj) {
return (arr.indexOf(obj) != -1);
}
EDIT:
This will not work on IE6, 7 or 8 though. The bes...
pandas dataframe columns scaling with sklearn
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221
I am not sure if previous versions of pandas prevented this but now the following snippet works ...
Finding ALL duplicate rows, including “elements with smaller subscripts”
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130
duplicated has a fromLast argument. The "Example" section of ?duplicated shows you how to use...
Print list without brackets in a single row
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12 Answers
12
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How to extract the decision rules from scikit-learn decision-tree?
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21 Answers
21
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Replacement for “rename” in dplyr
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148
dplyr version 0.3 added a new rename() function that works just like plyr::rename().
df <-...