ArcGIS Field Calculator中的语法错误

Question

I got a tiny script in ArcGIS which creates a hyperlink.

My code:

def Befahrung(value1, value2):
    if value1 is '':
        return ''
    else:
        return "G:\\Example\\" + str(value1) + "\\File_" + str(value2) + ".pdf"

The error (only when !Bezeichnun! contains a special character):

ERROR 000539: Error running expression: Befahrung(u" ",u"1155Mönch1")
Traceback (most recent call last):
  File "<expression>", line 1 in <module>
  File "<string>", line 5 in Befahrung
UnicodeEncodeError: 'ascii' codec can't encode character u'\xf6' in position 5: ordinal not in range(128)

!Bezeichnun! and !Auftrag! are both strings. It works very well until !Bezeichnun! contains a special character. I can't change the characters, I need to save them.

What do I have to change?

Answer 1

In Befahrung , you convert a string (Unicode in this case) to ASCII:

str(value1);
str(value2);

cannot work if value1 or value2 contain non-ASCII characters. You want to use

unicode(value1)

or better, use string formatting:

return u"G:\\Example\\{}\\File_{}.pdf".format(value1, value2)

(works in Python 2.7 and above)

Answer 2

I recommend reading the Python Unicode HOWTO . The error can be distilled to

>>> str(u"1155Mönch1")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xf6' in position 5: ordinal not in range(128)

If you know what character encoding you need (eg, UTF-8), you can encode it like

value1.encode('utf-8')