Always initialize your variables. PHP will automatically create a variable if it hasn't been initialized, but it's not good practice to rely on this feature.

当需要没有初始化的变量，PHP解释器会自动创建一个变量，但依靠这个特性来编程并不是一个好主意。

youdao

The location of this variable depends on the version of Windows, but it's typically found through the system control panel.

这个环境变量的位置依赖于Windows的版本，但是典型的情况下你可以通过系统的控制面板找到它。

youdao

It's easy to think of bind as being a way to define a variable, but that's not really what it does (and one of the points where you can get confused).

很容易误以为bind是一种定义变量的方法，但这实际上不是它的作用(这是引起混淆的原因之一)。

youdao

But it's variable because it doesn't always go off on the thousandth time.

但中奖比率是变化的,因为你并不总在拉杆一千次的时候中大奖。

耶鲁公开课 - 心理学导论课程节选

When you declare a pointer yourself manually, you do say char * the variable name because recall that's the same thing that we did earlier but we called it instead string.

当你手动声明一个指针是，你可以说char，*，变量名字,因为那是我早些时候做的事情,但是我们叫它为字符串。

哈佛公开课 - 计算机科学课程节选

"Patchy ice is possible to start New Year's Day but it is generally drier with variable amounts of cloud and plenty of sunny spells developing, " she said.

BBC: Weather in Wales improving after flooding on Monday

Traveling 120 miles an hour on a road built for cars can be perilous enough, but when you're -- almost literally -- heading into the unknown, it's a variable you can probably do without.

ENGADGET: Art Thompson, Red Bull Stratos' technical project director, talks circuit breakers, wind shear and biomedical data