UnicodeEncodeError when not running script from IDE
davea at davea.name
Tue Feb 12 21:51:22 CET 2013
On 02/12/2013 12:12 PM, Magnus Pettersson wrote:
>> < snip >
> #Here kanji = u"私"
> baseurl = u"http://www.romajidesu.com/kanji/"
> url = baseurl+kanji
> savefile([url]) #this test works now. uses: io.open(filepath, "a",encoding="UTF-8") as f:
> # This made the fetching of the website work.
You don't show the code that actually does the io.open(), nor the
url.encode, so I'm not going to guess what you're actually doing.
> Why did i have to write url.encode("UTF-8") when url already is unicode? I feel i dont have a good understanding of this.
> page = urllib2.urlopen(url.encode("UTF-8"))
utf-8 is NOT unicode; they are entirely different. Unicode is
conceptually 32 bits per character, and is an internal representation.
There are a million or so characters defined. Nearly always when you're
talking to an external device, you need bytes. Since you can't cram 32
bits into 8, you have to encode it. Examples of devices would be any
file, or the console. Notice that sometimes you can use unicode
directly for certain functions. For example, the Windows file name is
composed of Unicode characters, so Windows has function calls that
accept Unicode directly. But back to 8 bits:
One encoding is called ASCII, which is simply the bottommost 7 bits.
But of course it gets an error if there are any characters above 127.
Other encodings try to pick an 8 bit subset of the million possible
characters. Again, if you happen to have a character that's not in that
subset, you'll get an error.
There are also other encodings which are hard to describe, but
fortunately pretty rare these days.
Then there's utf-8, which uses a variable length bunch of bytes for
each character. It's designed to use the ASCII encoding for characters
which are below 128, but uses two or more bytes for all the other
characters. So it works out well when most characters happen to be ASCII.
Once encoded, a stream of bytes can only be successfully interpreted if
you use the same decoding when processing them.
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