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How can you find the height of text on an HTML canvas?
The spec has a context.measureText(text) function that will tell you how much width it would require to print that text, but I can't find a way to find out how tall it is. I know it's based on the font, but I don't know to convert a font string to a text height.
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Check if two linked lists merge. If so, where?
This question may be old, but I couldn't think of an answer.
26 Answers
26
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java: Class.isInstance vs Class.isAssignableFrom
...z.isAssignableFrom(Foo.class) will be true whenever the class represented by the clazz object is a superclass or superinterface of Foo.
clazz.isInstance(obj) will be true whenever the object obj is an instance of the class clazz.
That is:
clazz.isAssignableFrom(obj.getClass()) == clazz.isInstanc...
The written versions of the logical operators
This is the only place I've ever seen and , or and not listed as actual operators in C++. When I wrote up a test program in NetBeans, I got the red underlining as if there was a syntax error and figured the website was wrong, but it is NetBeans which is wrong because it compiled and ran as exp...
Eclipse RCP开发桌面程序 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...个依赖项，记住，一定要把我们自己，也就是com.blogjava.youxia.rcp_start加进依赖项，否则会出错。最开始的时候，就是这么一点小问题，让我浪费了几天时间。
再点击添加必须的插件，自动添加其它的依赖项。
再下...
What's the scope of a variable initialized in an if statement?
I'm new to Python, so this is probably a simple scoping question. The following code in a Python file (module) is confusing me slightly:
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How do you calculate the average of a set of circular data? [closed]
...ke starblue's answer wrong, it's just an exceptional case, as occurs in many geomteric problems.
– SmacL
Jan 29 '09 at 14:31
5
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How do I combine two data-frames based on two columns? [duplicate]
I know I can use the plyr and its friends to combine dataframes, and merge as well, but so far I don't know how to merge two dataframes with multiple columns based on 2 columns?
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覆盖equal时的通用约定 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...性、一致性1、自反性：x.equal(x) = true;
2、对称性：x.equal(y) = y.equal(x);
3、传递性：x.equal(y) = y.equal(z) = x.equal(z);
4、一致性：x.equal(y) 不改变值的情况下多次调用结果一致。
（假定x, y, z非null）
覆盖 equal 约定
When is “i += x” different from “i = i + x” in Python?
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This depends entirely on the object i.
+= calls the __iadd__ method (if it exists -- falling back on __add__ if it doesn't exist) whereas + calls the __add__ method1 or the __radd__ method in a few cases2.
From an API perspective, __iadd__...