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    <p>It's not that <code>std::string</code> performs poorly (as much as I dislike C++), it's that string handling is so heavily optimized for those other languages.</p> <p>Your comparisons of string performance are misleading, and presumptuous if they are intended to represent more than just that.</p> <p>I know for a fact that <a href="http://hg.python.org/cpython/file/3ecddf168f1f/Objects/stringobject.c" rel="nofollow noreferrer">Python string objects are completely implemented in C</a>, and indeed on Python 2.7, <a href="http://hg.python.org/cpython/file/3ecddf168f1f/Objects/stringobject.c#l1021" rel="nofollow noreferrer">numerous</a> <a href="http://hg.python.org/cpython/file/3ecddf168f1f/Objects/bytearrayobject.c#l340" rel="nofollow noreferrer">optimizations</a> exist due to the lack of separation between unicode strings and bytes. If you ran this test on Python 3.x you will find it considerably slower.</p> <p>Javascript has numerous heavily optimized implementations. It's to be expected that string handling is excellent here.</p> <p>Your Java result may be due to improper string handling, or some other poor case. I expect that a Java expert could step in and fix this test with a few changes.</p> <p>As for your C++ example, I'd expect performance to slightly exceed the Python version. It does the same operations, with less interpreter overhead. This is reflected in your results. Preceding the test with <code>s.reserve(limit);</code> would remove reallocation overhead.</p> <p>I'll repeat that you're only testing a single facet of the languages' <em>implementations</em>. The results for this test do not reflect the overall language speed.</p> <p>I've provided a C version to show how silly such pissing contests can be:</p> <pre><code>#define _GNU_SOURCE #include &lt;string.h&gt; #include &lt;stdio.h&gt; void test() { int limit = 102 * 1024; char s[limit]; size_t size = 0; while (size &lt; limit) { s[size++] = 'X'; if (memmem(s, size, "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26)) { fprintf(stderr, "zomg\n"); return; } } printf("x's length = %zu\n", size); } int main() { test(); return 0; } </code></pre> <p>Timing:</p> <pre><code>matt@stanley:~/Desktop$ time ./smash x's length = 104448 real 0m0.681s user 0m0.680s sys 0m0.000s </code></pre>
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    1. POWhy do std::string operations perform poorly?
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    1. USMatt Joiner
    1. USMatt Joiner
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    1. COFWIW the difference between Python 2.7 and 3.2 is just under 10%. It is possible that PEP 393 will remove that difference in Python 3.3. Also it might be worth mentioned that searching strings in Python uses a form of Boyer-Moore so when the string gets longer it should gain an advantage over languages that do a plain search.
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    2. CO@Matt: Well, the C program is too extreme... I didn't tried to make a battle or contest between languages, for each language has its optimization in different ways. I just want to find a language that can proceed strings with quite good efficiency. The program just described a case that a program reads from an input(console or socket), maybe decrypts it then, and searches through the string for a specified pattern. My test program simplified the procedure and was just a demo, of course. The result just reminds me C++ is not always the sharpest knife. And thanks anyway :)
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      1. USWu Shu
    3. CO@Wu Shu: If the specific pattern to search for is fixed and predetermined, you can construct an automaton to search for the pattern. This will be much faster than repeated calls to `std::string::find`.
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