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Deleting DataFrame row in Pandas based on column value
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What are the Ruby Gotchas a newbie should be warned about? [closed]
...s strict: 0, "" and [] are all evaluated to true. In C, the expression 0 ? 1 : 0 evaluates to 0 (i.e. false). In Ruby, however, it yields 1, as all numbers evaluate to true; only nil and false evaluate to false. A corollary to this rule is that Ruby methods by convention — for example, regular-exp...
Getting the first and last day of a month, using a given DateTime object
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Ruby - test for array
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edited Mar 30 at 18:35
siery
17311 silver badge1212 bronze badges
answered Oct 6 '09 at 20:23
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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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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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How can I get the behavior of GNU's readlink -f on a Mac?
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Which iOS app version/build number(s) MUST be incremented upon App Store release?
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