使用整数和字符串键计数数组

Question

echo count(array("1" => "A", 1 => "B", "C", 2 => "D"));

这输出2.我玩过它并注意到PHP在用作数组中的键时识别字符串数和整数相同.似乎整数是优先的.另外,当我对数组进行var_dump时,只显示包含值"B"和"D"的元素.我理解为什么"A"没有显示,但为什么"C"不在var_dump中？

Answer 1

你的数组基本上是按如下方式构建的:

Key "1" is an integer-like string, treat as integer 1
Assign "A" to key 1
Assign "B" to key 1 (overwrite "A")
No explicit key, take greatest key so far and add 1 = 2
Assign "C" to key 2
Assign "D" to key 2 (overwrite "C")

因此你得到的数组是 array(1=>"B",2=>"D");