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How to delete duplicate lines in a file without sorting it in Unix?
... do something like for f in *.txt; do gawk -i inplace '!seen[$0]++' "$f"; done
– Nick K9
Jan 17 '19 at 18:05
@NickK9 t...
Introducing FOREIGN KEY constraint may cause cycles or multiple cascade paths - why?
...
Because Stage is required, all one-to-many relationships where Stage is involved will have cascading delete enabled by default. It means, if you delete a Stage entity
the delete will cascade directly to Side
the delete will cascade directly to Card and b...
namedtuple and default values for optional keyword arguments
...'left', 'right')
>>> Node = namedtuple('Node', fields, defaults=(None,) * len(fields))
>>> Node()
Node(val=None, left=None, right=None)
Or better yet, use the new dataclasses library, which is much nicer than namedtuple.
>>> from dataclasses import dataclass
>>>...
Dump Mongo Collection into JSON format
...json format? Either on the shell or using java driver.I am looking for the one with best performance.
5 Answers
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How to properly create an SVN tag from trunk?
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I marked this as answer. Just one extra note. You can get an previous revision of the trunk and "tag" it as well. the command: svn copy -r 123 "svn.example.com/project/trunk" "svn.example.com/project/tags/1.0" -m "Tagging, but using older re...
Multiple submit buttons on HTML form – designate one button as default [duplicate]
...(note: positioning is used to push the button off-screen because display: none and visibility: hidden have browser-variable side-effects on whether the button is taken as default and whether it's submitted.)
share
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Why does auto a=1; compile in C?
...dy been dropped in C++98; the only thing that breaks is auto T a, which no-one was using anyway. (Somewhere in his papers on the history of the language, Stroustrup comments on this, but I can't find the exact reference right now.)
(*) String handling in B was interesting: you'd use arrays of int a...
What is a word boundary in regex?
...Correctamundo. \b is a zero-width assertion that matches if there is \w on one side, and either there is \W on the other or the position is beginning or end of string. \w is arbitrarily defined to be "identifier" characters (alnums and underscore), not as anything especially useful for English.
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jQuery vs document.querySelectorAll
...terface.
If you only want the selector engine from jQuery you can use the one jQuery itself is using: Sizzle That way you have the power of jQuerys Selector engine without the nasty overhead.
EDIT:
Just for the record, I'm a huge vanilla JavaScript fan. Nonetheless it's a fact that you sometimes n...
print call stack in C or C++
...ad, were nicely demangled for us.
Note that the first int calls is off by one line (28 instead of 27 and the second one is off by two lines (27 instead of 29). It was suggested in the comments that this is because the following instruction address is being considered, which makes 27 become 28, and ...