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How to delete from a text file, all lines that contain a specific string?
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To remove the line and print the output to standard out:
sed '/pattern to match/d' ./infile
To directly modify the file – does not work with BSD sed:
sed -i '/pattern to match/d' ./infile
Same, but for BSD sed (Mac OS X and FreeBSD) –...
Python regular expressions return true/false
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Match objects are always true, and None is returned if there is no match. Just test for trueness.
if re.match(...):
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Is there a generic constructor with parameter constraint in C#?
...has parameterless constructor, if you define a constructor with parameters and dont redefine the default constructor, there's no default constructor.
– Johnny5
Apr 30 '12 at 17:58
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Is it possible to make a Tree View with Angular?
... why not state your source? you wrote a post in that thread, and now you're posting a url here with your own name in it?
– Janus Troelsen
Sep 23 '12 at 0:56
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How do I declare an array of weak references in Swift?
...gt;.weakObjects()
NSHashTable Class Reference
Available in OS X v10.5 and later.
Available in iOS 6.0 and later.
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How to add not null constraint to existing column in MySQL
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Just use an ALTER TABLE... MODIFY... query and add NOT NULL into your existing column definition. For example:
ALTER TABLE Person MODIFY P_Id INT(11) NOT NULL;
A word of caution: you need to specify the full column definition again when using a MODIFY query. If you...
Ruby optional parameters
...his method: e.g. If you're trying to make the default value for scope true and you pass in false, scope ||= true won't work. It evaluates the same as nil and will set it to true
– Joshua Pinter
Nov 10 '11 at 5:32
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【App Inventor 2 数据可视化】使用柱状图和饼图收集数据 - App应用开发 - ...
学习图表相关组件的入门教程，原文系翻译官方英文文章，侵删。文章内容质量较高，不过排版较乱（手机版排版不好，请使用PC浏览器查看），凑合着看吧~
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Calculate the median of a billion numbers
If you have one billion numbers and one hundred computers, what is the best way to locate the median of these numbers?
25 A...
Generic type conversion FROM string
... store "properties" for another class. These properties simply have a name and a value. Ideally, what I would like is to be able to add typed properties, so that the "value" returned is always of the type that I want it to be.
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