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What's the deal with a leading underscore in PHP class methods?

...private with an underscore. In some older classes you'll see /**private*/ __foo() { to give it some extra weight. I've never heard of developers prefacing all their methods with underscores, so I can't begin to explain what causes that. ...
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How can I print the contents of a hash in Perl?

... Easy: print "$_ $h{$_}\n" for (keys %h); Elegant, but actually 30% slower (!): while (my ($k,$v)=each %h){print "$k $v\n"} share | im...
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Why can't (or doesn't) the compiler optimize a predictable addition loop into a multiplication?

... It does now -- at least, clang does: long long add_100k_signed(int *data, int arraySize) { long long sum = 0; for (int c = 0; c < arraySize; ++c) if (data[c] >= 128) for (int i = 0; i < 100000; ++i) sum += data[c]; re...
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Can I have onScrollListener for a ScrollView?

...dited Sep 16 '16 at 6:48 Pavneet_Singh 33.3k55 gold badges3939 silver badges5757 bronze badges answered Apr 29 '14 at 13:06 ...
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Characters allowed in a URL

...738 specification: Thus, only alphanumerics, the special characters "$-_.+!*'(),", and reserved characters used for their reserved purposes may be used unencoded within a URL. EDIT: As @Jukka K. Korpela correctly points out, this RFC was updated by RFC 3986. This has expanded and clarified...
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What are the details of “Objective-C Literals” mentioned in the Xcode 4.4 release notes?

... This part is new. Expression Literals When you have an expression (M_PI / 16 for example) you should put it inside parenthesis. This syntax works for numeral expressions, booleans, finding an index in a (C-) string, boolean values, enum constants, and even character strings! NSNumber *piO...
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使用std::string作为std::map的key出错解决 - C/C++ - 清泛网 - 专注C/C++及内核技术

...0\vc\include\xstddef(180): error C2784: “bool std::operator <(const std::_Tree<_Traits> &,const std::_Tree<_Traits> &)”: 未能从“const std::string”为“const std::_Tree<_Traits> &”推导 模板 参数 1> c:\program files (x86)\microsoft visual studio 11.0\vc\include\xtree(2245...
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How do I partially update an object in MongoDB so the new object will overlay / merge with the exist

...e data then? You know you can do the following: db.collection.update( { _id:...} , { $set: someObjectWithNewData } share | improve this answer | follow | ...
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How can I use UUIDs in SQLAlchemy?

... is an example: from sqlalchemy.dialects.postgresql import UUID from flask_sqlalchemy import SQLAlchemy import uuid db = SQLAlchemy() class Foo(db.Model): # id = db.Column(db.Integer, primary_key=True) id = db.Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, unique=True, n...
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How do I make a textbox that only accepts numbers?

... with this two event handlers on a standard TextBox: private void textBox1_KeyPress(object sender, KeyPressEventArgs e) { if (!char.IsControl(e.KeyChar) &amp;&amp; !char.IsDigit(e.KeyChar) &amp;&amp; (e.KeyChar != '.')) { e.Handled = true; } // only allow one de...