Question

I’m working on a python script to created a mongo collection based on a MySql db. The problem is with the micro sign character:

bson.errors.InvalidStringData: strings in documents must be valid UTF-8: '\xb5g'

I tried encoding/decoding the value with different codes(utf-8, latin-1, cp1252,iso-8859-2) without success but I always get the following error:

UnicodeDecodeError: 'ascii' codec can't decode byte 0xb5 in position 0: ordinal not in   range(128)

This is the code to get the data from the mysql db. The database is the USDA one 0:

    # -*- encoding: utf-8 -*-

    import MySQLdb
    mysqldb = MySQLdb.connect(DBCONF)
    cursor = mysqldb.cursor()
    foodid = 1001
    q = (
        ' SELECT nut.Nutr_Val,'
        ' nutdef.Units,'
        ' nutdef.NutrDesc, nutdef.Tagname'
        ' FROM food_des AS f'
        ' JOIN nutrient AS nut ON nut.NDB_No = f.NDB_No'
        ' JOIN nutrient_def AS nutdef ON nutdef.Nutr_No = nut.Nutr_No'
        ' WHERE f.NDB_No = %s'
    ) % str(foodid)
    self.cursor.execute(q)

The field with the micro sign character is the nutdef.Units one.

Answer 1

Just try decoding the characters as latin-1:

a = '\xb5g'
# '\xb5g'
print a
# ?g

b = a.decode('latin-1')
print b
# µg

b
# u'\xb5g'

Or you can fix this in your MySQL connection by telling it to use unicode on all CHAR, VARCHAR, and TEXT fields:

MySQLdb.connect(..., use_unicode=True)