Reading UTF-8 text files with ReadList

问题:

Is it possible to use ReadList to read UTF-8 (or any other) encoded text files using ReadList[..., Word], or is it ASCII-only? If it's ASCII-only, is it possible to "fix" the encoding of the already read data with good performance (i.e. preserving the performance advantages of ReadList over Import)?

_{Import[..., CharacterEncoding -> "UTF8"] works but it's quite a bit slower than ReadList. $CharacterEncoding has no effect on ReadList}

Download a sample UTF-8 encoded file here.

For testing performance on a large input, see the test file in this question.

---

Here are the timings of the answers on a large-ish text file:

Import

In[2]:= Timing[
 data = Import[file, "Text"];
 ]

Out[2]= {5.234, Null}

Heike

In[4]:= Timing[
 data = ReadList[file, String];
 FromCharacterCode[ToCharacterCode[data], "UTF8"];
 ]

Out[4]= {4.328, Null}

Mr. Wizard

In[5]:= Timing[
 string = FromCharacterCode[BinaryReadList[file], "UTF-8"];
 ]

Out[5]= {2.281, Null}

回答1:

If I leave out Word, this works:

$CharacterEncoding = "UTF-8";

ReadList["UTF8.txt"]

This however is a failure, because the data is not read as strings.

Please try this on a larger file and report its performance:

FromCharacterCode[BinaryReadList["UTF8.txt"], "UTF-8"]

回答2:

This seems to work

FromCharacterCode[ToCharacterCode[ReadList["raw.php.txt", Word]], "UTF-8"]

The timings I get for the linked test file are

FromCharacterCode[ToCharacterCode[ReadList["test.txt", Word]], "UTF-8"]); // Timing

(* ==> {0.000195, Null} *)

Import["test.txt", "Text"]; // Timing

(* ==> {0.01784, Null} *)