php 如何计算一个非常大的字符串中的新行？
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how to count new lines in a very big string?
提问by rsk82
The problem reduces to counting \ncharacters, so is there a function that can do it on a huge strings, since explode() wastes too much memory.
问题归结为计数\n字符，因此是否有一个函数可以在巨大的字符串上执行此操作，因为explode() 浪费了太多内存。
回答by George Cummins
回答by Carlos Precioso
You can use PHP's substr_count()function: http://www.php.net/manual/en/function.substr-count.php
你可以使用PHP的substr_count()功能：http: //www.php.net/manual/en/function.substr-count.php
substr_count($myString, "\n");
substr_count($myString, "\n");
It will give you an integer with the number of occurrences.
它会给你一个带有出现次数的整数。
回答by Hoàng V? Tgtt
i Think substr_count( $your_string, "\n" ); should be:
我认为 substr_count( $your_string, "\n" ); 应该：
$numLine = substr_count( $your_string, "\n" ) +1;
But I use this:
但我用这个：
$numLine = count(explode("\n",$your_string));
it always return correct result
它总是返回正确的结果
回答by Trey
$count=preg_match_all ('/\n/',$str);
