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How do you match only valid roman numerals with a regular expression?
...L|L?X{0,3})(IX|IV|V?I{0,3})$
Breaking it down, M{0,4} specifies the thousands section and basically restrains it to between 0 and 4000. It's a relatively simple:
0: <empty> matched by M{0}
1000: M matched by M{1}
2000: MM matched by M{2}
3000: MMM matched by M{3}
4000:...
Best way to merge two maps and sum the values of same key?
I want to merge them, and sum the values of same keys. So the result will be:
15 Answers
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Xcode 6 beta 2 issue exporting .ipa: “Your account already has a valid iOS distribution certificate”
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This is what worked for me.
On my machine I kept both Xcode 5 and Xcode 6 beta.
From Xcode 6 beta, Archive the project. Close Xcode 6.
Open Xcode 5, go to Organizer and export as Ad Hoc build with proper provisioning profile.
That's it!
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How do I shuffle an array in Swift?
How do I randomize or shuffle the elements within an array in Swift? For example, if my array consists of 52 playing cards, I want to shuffle the array in order to shuffle the deck.
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Calendar returns wrong month [duplicate]
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Months are indexed from 0 not 1 so 10 is November and 11 will be December.
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Writing to an Excel spreadsheet
... to write some data from my program to a spreadsheet. I've searched online and there seem to be many packages available (xlwt, XlsXcessive, openpyxl). Others suggest to write to a .csv file (never used CSV and don't really understand what it is).
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What really is a deque in STL?
I was looking at STL containers and trying to figure what they really are (i.e. the data structure used), and the deque stopped me: I thought at first that it was a double linked list, which would allow insertion and deletion from both ends in constant time, but I am troubled by the promise made ...
What is the difference between LL and LR parsing?
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At a high level, the difference between LL parsing and LR parsing is that LL parsers begin at the start symbol and try to apply productions to arrive at the target string, whereas LR parsers begin at the target string and try to arrive back at the start symbol.
An LL parse i...
What is the optimal Jewish toenail cutting algorithm?
...automatically trim toenails, so that users can simply put their feet in it and run it instead of having to manually do it by biting them or using nail clippers.
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What is the difference between Python's list methods append and extend?
What's the difference between the list methods append() and extend() ?
20 Answers
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