there are strange characters at the beginning of a file I'm editing (using textmate..)
I don't know when they appeared, they're invisible in textmate but my script that reads the file goes crazy..
this is the first few chars in the file (as seen with od command):
0000000 177377 000120 000105 000117 000120 000114 000105 000072
the first 2 shouldn't be there I think.. maybe they were caused by some strange dropbox sync? Or something else.. but they tend to reappear (I don't yet know when..)
My question: what is that 177377 and a simple way to remove it in my ruby script?
thanks
The 000000 177377 (hex 0x0000FEFF) is a byte-order mark (BOM). It indicates to consumers that the remainder of the file is in big-endian UTF-32 encoding. This may not be correct in your case, but that's what the bytes indicate.
What to do with it is a little tricky. In general, the BOM does accurately represent the encoding of the following data. Detecting and skipping it and treating the subsequent content as if it were in your local default charset is usually going to be the wrong thing to do, even though it seems to be correct here. Instead, I'd try to figure out why your editor is inserting an incorrect BOM and whether there's a way to disable it.
Related
I am trying to use wget -m <address> to download the contents of an FTP server. A lot of the content is icelandic and so contains a bunch of weird characters that I think are causing issues as I keep seeing:
Incomplete or invalid multibyte sequence encountered
I have tried adding flags such as --restrict-file-names=nocontrol but to no avail.
I have also tried using lftp but doesn't seem to make any difference.
According to wget manual
If you specify ‘nocontrol’, then the escaping of the control
characters is also switched off.
that is it as actually more permissive than default, bunch of weird characters suggest you have some issues with getting encoding right and therefore ascii seems to be best fit for your use case
The ‘ascii’ mode is used to specify that any bytes whose values are
outside the range of ASCII characters (that is, greater than 127)
shall be escaped. This can be useful when saving filenames whose
encoding does not match the one used locally.
As I do not have ability to test, please try it and write about result it give.
I have a CSV with content that is UTF-8 encoded. However, various applications and systems errorneously detect the encoding of the CSV as Windows-1252, which breaks all the special characters in the file (e.g. Umlauts).
I can see that Sublime Text (on Windows) for example also automatically detects the wrong Windows-1252 encoding, when opening the file for the first time, showing garbled text where special characters are supposed to be.
When I choose Reopen with Encoding » UTF-8, everything will look fine, as expected.
Now, to find the source of the error I thought it might help to figure out, why these applications are not automatically detecting the correct encoding in the first place. May be there is a stray character somewhere with the wrong encoding for example.
The CSV in question is actually an automatically generated product export of a Magento 2 installation. Recently the character encodings broke and I am currently trying to figure out what happened - hence my investigation on why this export is detected as Windows-1252.
Is there any reliable way of figuring out why the automatic detection of applications like Sublime Text assume the wrong character encoding?
This is what I did in the end to find out why the file was not detected as UTF-8, i.e. to find the characters that were not encoded in UTF-8. Since PHP is more readily available to me, I decided to simply use the following script, to force convert anything that is not UTF-8 to UTF-8, using the very handy neitanod/forceutf8 library.
$before = file_get_contents('export.csv');
$after = \ForceUTF8\Encoding::toUTF8($before);
file_put_contents('export.fixed.csv', $after);
Then I used a file comparison tool like Beyond Compare to compare the two resulting CSVs, in order to see more easily which characters were not originally encoded in UTF-8.
This in turn showed me that only one particular column of the export was affected. Upon further investigation I found out that the contents of that column were processed in PHP with the following preg_replace:
$value = preg_replace('/([^\pL0-9 -])+/', '', $value);
Using \p in the regular expression had an unknown side effect: all the special characters were converted to another encoding. A quick solution to this is to use the u flag on the regex (see regex pattern modifiers reference). This forces the resulting encoding of this preg_replace to be UTF-8. See also this answer.
I wrote a script with German special characters e.g. ü.
However, whenever I close R and reopen the script the characters are substituted:
Before "für"; "hinzufügen"; "Ø" - After "für"; "hinzufügen"; "Ã".
I tried to remedy it using save with encoding and choosing UTF-8 as it is stated here but it did not work.
What am I missing?
You don't say what OS you're using, but this kind of thing really only happens on Windows nowadays, so I'll assume that.
The problem is that Windows has a local encoding that is not UTF-8. It is commonly something like Latin1 in English-speaking countries. I'm not sure what encoding people use in German-speaking countries, if that's where you are. From the junk you saw, it looks as though you saved the file in UTF-8, then read it using your local encoding. The encodings for writing and reading have to match if you want things to work.
In RStudio you can try "Reopen with encoding..." and specify UTF-8, and you'll probably get your original back, as long as you haven't saved it after the bad read. If you did that, you've got a much harder cleanup to do.
(Using Ruby 1.8)
I only have a brief understanding of encoding and such...but what I want to know is, in any given script handling any given text-file, is there some universal library or call I need to make to turn non-standard characters into their nearest printable equivalent. I realize there's no "all-in-one" fix, but this is for a English (U.S. gov't) text file, and so I'm wondering if there's something that mitigates what must be a relatively common issue in English text formatting.
For example, in a text file, I have an entry like this:
0-823
That hyphen is just literally a hyphen as I've typed it out. In the file though, it's something that looks like a hyphen (an n-dash?) but when copy and pasting it...for example, into this browser text box, it doesn't show up.
Printing it out via a Ruby script gets this:
08�23
How do I get my script to resolve it into a dash. Or something other than a gremlin?
It's very common to run into hyphen-like characters and dashes, especially in the output of word-processors. Converting them isn't too hard if you know what the byte is that represents the character, but gets to be a pain when you get a document with several different ones. It gets worse as you throw other accented characters into the mix.
Ruby 1.8 doesn't support multibyte and Unicode character sets as well as 1.9+, but you can work around that somewhat by using the Iconv library.
Iconv lets you convert between various character-sets, such as US-ASCII, ISO-8859-1 and WIN-1252. It's smarter than a regex, because it knows how to convert from accented characters, to similarly looking characters, or ignore them if nothing similar exists, allowing your transliteration to degrade gracefully.
I have some example code in an answer to a related question. Also read James Grey's article linked in the answer. It explains the problem and ways to fix it, ending up with recommending Iconv too.
You could whitelist with gsub:
string.gsub(/[^a-zA-Z0-9]/)
Without knowing more information, I can't build the perfect regex for you, but the general idea is to replace anything that's not what you're expecting (anything not a letter or number or expected symbols).
My program has to read files that use various encodings. They may be ANSI, UTF-8 or UTF-16 (big or little endian).
When the BOM (Byte Order Mark) is there, I have no problem. I know if the file is UTF-8 or UTF-16 BE or LE.
I wanted to assume when there was no BOM that the file was ANSI. But I have found that the files I am dealing with often are missing their BOM. Therefore no BOM may mean that the file is ANSI, UTF-8, UTF-16 BE or LE.
When the file has no BOM, what would be the best way to scan some of the file and most accurately guess the type of encoding? I'd like to be right close to 100% of the time if the file is ANSI and in the high 90's if it is a UTF format.
I'm looking for a generic algorithmic way to determine this. But I actually use Delphi 2009 which knows Unicode and has a TEncoding class, so something specific to that would be a bonus.
Answer:
ShreevatsaR's answer led me to search on Google for "universal encoding detector delphi" which surprised me in having this post listed in #1 position after being alive for only about 45 minutes! That is fast googlebotting!! And also amazing that Stackoverflow gets into 1st place so quickly.
The 2nd entry in Google was a blog entry by Fred Eaker on Character encoding detection that listed algorithms in various languages.
I found the mention of Delphi on that page, and it led me straight to the Free OpenSource ChsDet Charset Detector at SourceForge written in Delphi and based on Mozilla's i18n component.
Fantastic! Thank you all those who answered (all +1), thank you ShreevatsaR, and thank you again Stackoverflow, for helping me find my answer in less than an hour!
Maybe you can shell out to a Python script that uses Chardet: Universal Encoding Detector. It is a reimplementation of the character encoding detection that used by Firefox, and is used by many different applications. Useful links: Mozilla's code, research paper it was based on (ironically, my Firefox fails to correctly detect the encoding of that page), short explanation, detailed explanation.
Here is how notepad does that
There is also the python Universal Encoding Detector which you can check.
My guess is:
First, check if the file has byte values less than 32 (except for tab/newlines). If it does, it can't be ANSI or UTF-8. Thus - UTF-16. Just have to figure out the endianness. For this you should probably use some table of valid Unicode character codes. If you encounter invalid codes, try the other endianness if that fits. If either fit (or don't), check which one has larger percentage of alphanumeric codes. Also you might try searchung for line breaks and determine endianness from them. Other than that, I have no ideas how to check for endianness.
If the file contains no values less than 32 (apart from said whitespace), it's probably ANSI or UTF-8. Try parsing it as UTF-8 and see if you get any invalid Unicode characters. If you do, it's probably ANSI.
If you expect documents in non-English single-byte or multi-byte non-Unicode encodings, then you're out of luck. Best thing you can do is something like Internet Explorer which makes a histogram of character values and compares it to histograms of known languages. It works pretty often, but sometimes fails too. And you'll have to have a large library of letter histograms for every language.
ASCII? No modern OS uses ASCII any more. They all use 8 bit codes, at least, meaning it's either UTF-8, ISOLatinX, WinLatinX, MacRoman, Shift-JIS or whatever else is out there.
The only test I know of is to check for invalid UTF-8 chars. If you find any, then you know it can't be UTF-8. Same is probably possible for UTF-16. But when it's no Unicode set, then it'll be hard to tell which Windows code page it might be.
Most editors I know deal with this by letting the user choose a default from the list of all possible encodings.
There is code out there for checking validity of UTF chars.