pythonpython-2.7vcf-vcardvobject

Compare two vcards

I have two vcards :

vcard1 = "BEGIN:VCARD
          VERSION:3.0
          N;CHARSET=UTF-8:Name;;;;
          TEL:0005555000
          END:VCARD"

vcard2 = "BEGIN:VCARD
      VERSION:3.0
      N;CHARSET=UTF-8:Name;;;;
      TEL:0005555000
      EMAIL;CHARSET=UTF-8:my_email@email.com
      END:VCARD"

As you can see the only difference is that the second vcard has an additional attribute which is EMAIL? Are these two vcards could be considered as equal using code ?

import vobject
print(vobject.readOne(vcard1).serialize()==vobject.readOne(vcard2).serialize())
Solution

  • Solution

    The first rule for any comparison is to define the basis of comparison. You can even compare apples and oranges, provided you are looking for a quantity that can be compared: such as "how many apples vs. oranges" or "weight of 5-apples vs. 5-oranges". The point being the definition of underlying basis of comparison must be unambiguous.

    Note: I will use the data from the Dummy Data section below.

    Extending this concept to your use-case, you can compare the vcards against each field and then also compare against all fields. For example, I have shown you three ways to compare them:

    Obviously, in this case if you compare the serialized versions of vcard1 and vcard2, it would return False as the content of these two vcards are different.

    vc1.serialize()==vc2.serialize() # False

    Example

    In each case (A1, A2, A3), the custom function compare_vcards() returns two things:

    But you will have to define your own business logic to determine what you consider as a match and what is not. What I have shown here should help you get started though.

    ## Example - A1
#  Compare ONLY COMMON fields b/w vc1 and vc2
match, summary = compare_vcards(vc1, vc2, mode='common')
print(f'match:   \t{match}')
print(f'summary: \t{summary}')

## Output
# match:    {'n': True, 'tel': True, 'version': True}
# summary:  {'abs_match': True, 'rel_match': 1.0}

## Example - A2
#  Compare ALL fields b/w vc1 and vc2
match, summary = compare_vcards(vc1, vc2, mode='all')
print(f'match:   \t{match}')
print(f'summary: \t{summary}')

## Output
# match:    {'tel': True, 'email': False, 'n': True, 'version': True}
# summary:  {'abs_match': False, 'rel_match': 0.75}

## Example - A3
#  Compare ONLY COMMON USER-SPECIFIED fields b/w vc1 and vc2
match, summary = compare_vcards(vc1, vc2, fields=['email', 'n', 'tel'])
print(f'match:   \t{match}')
print(f'summary: \t{summary}')

## Output
# match:    {'email': False, 'n': True, 'tel': True}
# summary:  {'abs_match': False, 'rel_match': 0.6666666666666666}

    Code

    def get_fields(vc1, vc2, mode='common'):
    if mode=='common':
        fields = set(vc1.sortChildKeys()).intersection(set(vc2.sortChildKeys()))
    else:
        # mode = 'all'
        fields = set(vc1.sortChildKeys()).union(set(vc2.sortChildKeys()))
    return fields

def compare_vcards(vc1, vc2, fields=None, mode='common'):
    if fields is None:
        fields = get_fields(vc1, vc2, mode=mode) 
    match = dict(
        (field, str(vc1.getChildValue(field)).strip()==str(vc2.getChildValue(field)).strip()) 
        for field in fields
    )
    summary = {
        'abs_match': all(match.values()), 
        'rel_match': sum(match.values()) / len(match)
    }
    return match, summary

    Dummy Data

    vcard1 = """
BEGIN:VCARD
VERSION:3.0
N;CHARSET=UTF-8:Name;;;;
TEL:0005555000
END:VCARD
"""

vcard2 = """
BEGIN:VCARD
VERSION:3.0
N;CHARSET=UTF-8:Name;;;;
TEL:0005555000
EMAIL;CHARSET=UTF-8:my_email@email.com
END:VCARD
"""

# pip install vobject
import vobject

vc1 = vobject.readOne(vcard1)
vc2 = vobject.readOne(vcard2)

    References