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scrapy xpath抓取节点的文本innerText、innerHTML、outerHTML - 更多技术 -...
scrapy xpath抓取节点的文本innerText、innerHTML、outerHTML假设抓取：<p> xx<b>x< b>< p> 抓取p节点本身，得到的内容：<p>xx<b>x< b>< p>response xpath(& 39; div[@class="question"] div[2] div[2] div[1] p[1]& 39;) extract() 抓 假设抓取：
<p>
xx<b>x</b>
</p>
scra...
Why do std::shared_ptr work
...g delete). When the shared_ptr is destroyed, it calls that stored function and that will call the deleter.
A simple sketch of the type erasure that is going on simplified with std::function, and avoiding all reference counting and other issues can be seen here:
template &lt;typename T&gt;
void del...
How many bytes in a JavaScript string?
...6 text:
4.3.16 String Value
A string value is a member of the type String and is a
finite ordered sequence of zero or
more 16-bit unsigned integer values.
NOTE Although each value usually
represents a single 16-bit unit of
UTF-16 text, the language does not
place any restrictions or requirements
on...
Invalid date format specification in gemspec
I am getting the following error when I try to use gems in windows, and I also referred to
this stackoverflow post and updated rubygems and rails. But nothing could solve the problem.
...
What is the use of having destructor as private?
...en "friend"ed) responsible for counting the number of references to itself and delete it when the number hits zero. A private dtor would prevent anybody else from deleting it when there were still references to it.
For another instance, what if you have an object that has a manager (or itself) tha...
'sudo gem install' or 'gem install' and gem locations
Running ' sudo gem list --local ' and ' gem list --local ' give me differing results. My gem path is set to my home folder and only contains the gems from ' gem list --local '.
...
What is the difference between SQL, PL-SQL and T-SQL?
What is the difference between SQL, PL-SQL and T-SQL?
6 Answers
6
...
Javascript Equivalent to C# LINQ Select
...c must be either a' +
'function or an object of properties and values to filter by');
}
};
Array.prototype.firstOrDefault = function(func){
return this.where(func)[0] || null;
};
Usage:
var persons = [{ name: 'foo', age: 1 }, { name: 'bar', age: 2 }];
// returns an arr...
Oracle “(+)” Operator
I am checking some old SQL Statements for the purpose of documenting them and probably enhancing them.
4 Answers
...
Is pass-by-value a reasonable default in C++11?
In traditional C++, passing by value into functions and methods is slow for large objects, and is generally frowned upon. Instead, C++ programmers tend to pass references around, which is faster, but which introduces all sorts of complicated questions around ownership and especially around memory ma...