增加在PHP无法初始化数组值 [英] Increasing not initialize array value in php

问题描述

海兰
我有一个foreach循环，增加了数组键到另一个阵列。我想知道这是否是安全的增加（与++）和未初始化的元素。
此刻我的code是：

Hy I have a foreach loop that adds array keys to another array. I wanted to know if it' safe to increment (with ++) and uninitialize element. At the moment my code is:

foreach($SociBdP as $id=>$socio)
{
    if(!isset($provenienza[$option_name]))
        $provenienza[$option_name]=0;
    $provenienza[$option_name]++;
}

我想知道，如果它的安全做

I wanted to know if it's safe to do

foreach($SociBdP as $id=>$socio)
{
    $provenienza[$option_name]++;
}

，或者如果存在这样的风险（如在C ++），该阵列的默认值不为0

or if there is a risk (like in c++) that the default value of the array isn't 0

推荐答案

虽然这是一个的记录的行为你可以信任：

While it's a documented behaviour you can trust:

这是没有必要初始化在PHP变量但它是一个
  非常好的做法。未初始化的变量有一个默认值
  根据上下文其类型在它们所使用的 - 布尔
  默认为FALSE，整形和浮点默认为零，字符串（例如
  回声使用）设置为空字符串和数组成为空
  数组。

It is not necessary to initialize variables in PHP however it is a very good practice. Uninitialized variables have a default value of their type depending on the context in which they are used - booleans default to FALSE, integers and floats default to zero, strings (e.g. used in echo) are set as an empty string and arrays become to an empty array.

...这也美元，以通知的好处p $ pvents你，因为你需要降低下来您的错误报告设置，这样他们就不会在开发阶段显示出来：

... it also prevents you from taking benefit of notices since you need to lower down your error reporting settings so they don't show up in the development phase:

var_dump($foo);

Notice: Undefined variable: foo in D:\tmp\borrame.php on line 3
NULL

通告常常被看作是由一个新手，但烦恼，他们实际上是当场傻错别字一个了不起的工具。

Notices are often seen as an annoyance by newbies but they're actually a terrific tool to spot silly typos.

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