PHP print_r大数组到变量不起作用 [英] PHP print_r large array to variable not working

问题描述

我正在尝试将大数组print_r压缩到文件中以对其进行调试.我尝试了2种方法:

I'm trying to print_r a large array to a file to debug it. I've tried 2 methods:

$arr = get_large_array();
file_put_contents('file.txt', print_r($arr, true));

和

$arr = get_large_array();
ob_start();
print_r($arr);
file_put_contents('file.txt', ob_get_contents());
ob_end_clean();

在这两种情况下，都不会创建file.txt，并且正在回显$arr，就像运行了print_r($arr)一样.这是怎么回事?

In both cases, file.txt is not being created, and $arr is being echoed just like as if I had run print_r($arr). What's going on here?

推荐答案

问题在于，在内部，print_r($arr, true)像在第二个示例中一样简单地使用输出缓冲.因此，在幕后，这两种方法都是等效的.但是为什么输出缓冲不起作用?

The problem is that internally, print_r($arr, true) simply uses output buffering as in the second example. So behind the scenes, both methods are equivalent. But why is output buffering not working?

我很感兴趣，我用$arr = array();替换了$arr = get_large_array();.令我惊讶的是，创建了file.txt并且没有任何输出.我有个主意我将$arr改回了大数组，运行了代码，然后向下滚动到输出的末尾.果然，它被截断了.我查看了错误日志，在print_r行上发生了20个左右的内存不足"错误.在处理大型数组时，print_r内存不足，崩溃并忽略了file_put_contents和ob_end_clean，显示了上述症状.

Intrigued, I replaced $arr = get_large_array(); with $arr = array();. To my surprise, file.txt was created and there was no output. I had an idea. I changed $arr back to the large array, ran the code, and scrolled down to the end of the output. Sure enough, it was being truncated. I looked in the error log, and there were 20 or so "out of memory" errors occurring on the print_r line. In dealing with the large array, print_r ran out of memory, crashed and ignored the file_put_contents and the ob_end_clean, displaying the aforementioned symptoms.

对我来说，解决方案是增加内存限制:

For me, the solution was to increase the memory limit:

ini_set('memory_limit', '1024M');

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