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Home Backend Development PHP Tutorial 【php】echo與var_dump

【php】echo與var_dump

Jun 23, 2016 pm 01:27 PM

echo與var_dump的核心功能同樣是沒有區(qū)別的,皆為“輸出變量的值”,但是echo偏向于產品,給客戶看的,調試人員、編程人員更適合使用var_dump來輸出變量,在調試的時候,告別難以使用的echo吧!

echo只能輸出變量的值,var_dump能將變量的值與類型同時輸出。

如果不做任何處理,在php中是無法直接輸出一個數(shù)組的,需要用到一個for循環(huán)才可以,如果直接用echo輸出一個數(shù)組,php會報錯,但var_dump卻是可以的,還輸出得挺完美,無須通過任何的處理。

再有的就是類變量的輸出,如果不作任何處理,echo同樣是會報錯的,var_dump則可以輕松輸出。

用一個例子還說明這個問題,代碼如下:

<?php //對于普通變量的輸出$i=1;echo $i;echo "<br>";//華麗的分隔符,請忽略var_dump($i);echo "<br>";//華麗的分隔符,請忽略//對于數(shù)組的輸出$arr=array(1,2,3);echo $arr;//輸出警告echo "<br>";//華麗的分隔符,請忽略var_dump($arr);echo "<br>";//華麗的分隔符,請忽略//對于類的輸出class Test{	public $i="i";	public $j="j";	}$test = new Test(); var_dump($test);echo "<br>";//華麗的分隔符,請忽略echo $test;//輸出錯誤echo "<br>";//華麗的分隔符,請忽略?>
輸出結果如下:


可以看到var_dump對于變量、數(shù)組、類的輸出,有著很好的表現(xiàn),通過var_dump能夠輕易地觀察出變量、數(shù)組、類此時的值為多少。而echo則報錯成狗,當然,在普通網(wǎng)頁的輸出,我們也不希望軟件產品客戶看到var_dump輸出的信息,所以echo還是最基礎的東西。

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