How to return the values of dictionary key that has gained new values in a different dictionary

I have question a bit similar to:Replacing the value of a Python dictionary with the value of another dictionary that matches the other dictionaries key

However in my case I got two dictionaries

dict1 = {'foo' : ['val1' , 'val2' , 'val3'] , 'bar' : ['val4' , 'val5']}



dict2 = {'foo' : ['val2', 'val10', 'val11'] , 'bar' : ['val1' , 'val4']}

What I want to return is

dict3 = {'foo' : ['val10', 'val11'] , 'bar' : ['val1']}

and the opposite which is

dict4 = {'foo' : ['val1', 'val3'] , 'bar' : ['val5']}

where dict3 returns a dictionary of the values the keys 'foo' and 'bar' has gained in dict2 and the dict4 is a dictionary of the values the keys 'foo' and 'bar' has lost in dict2

One way I have tried solving this is to:

 iterate over both dictionaries then

    if key of dict1 == key of dict2

       return the values of the key in dict1 and compare with the values in dict2

       return the values that aren't in both 

       as a dictionary of the key and those values

This idea isn't working and obviously highly inefficient. I was hoping there is a more efficient working way to do this

asked Nov 15 '18 at 2:17

Mykel

336

add a comment |

I have question a bit similar to:Replacing the value of a Python dictionary with the value of another dictionary that matches the other dictionaries key

However in my case I got two dictionaries

dict1 = {'foo' : ['val1' , 'val2' , 'val3'] , 'bar' : ['val4' , 'val5']}



dict2 = {'foo' : ['val2', 'val10', 'val11'] , 'bar' : ['val1' , 'val4']}

What I want to return is

dict3 = {'foo' : ['val10', 'val11'] , 'bar' : ['val1']}

and the opposite which is

dict4 = {'foo' : ['val1', 'val3'] , 'bar' : ['val5']}

where dict3 returns a dictionary of the values the keys 'foo' and 'bar' has gained in dict2 and the dict4 is a dictionary of the values the keys 'foo' and 'bar' has lost in dict2

One way I have tried solving this is to:

 iterate over both dictionaries then

    if key of dict1 == key of dict2

       return the values of the key in dict1 and compare with the values in dict2

       return the values that aren't in both 

       as a dictionary of the key and those values

This idea isn't working and obviously highly inefficient. I was hoping there is a more efficient working way to do this

asked Nov 15 '18 at 2:17

Mykel

336

add a comment |

I have question a bit similar to:Replacing the value of a Python dictionary with the value of another dictionary that matches the other dictionaries key

However in my case I got two dictionaries

dict1 = {'foo' : ['val1' , 'val2' , 'val3'] , 'bar' : ['val4' , 'val5']}



dict2 = {'foo' : ['val2', 'val10', 'val11'] , 'bar' : ['val1' , 'val4']}

What I want to return is

dict3 = {'foo' : ['val10', 'val11'] , 'bar' : ['val1']}

and the opposite which is

dict4 = {'foo' : ['val1', 'val3'] , 'bar' : ['val5']}

where dict3 returns a dictionary of the values the keys 'foo' and 'bar' has gained in dict2 and the dict4 is a dictionary of the values the keys 'foo' and 'bar' has lost in dict2

One way I have tried solving this is to:

 iterate over both dictionaries then

    if key of dict1 == key of dict2

       return the values of the key in dict1 and compare with the values in dict2

       return the values that aren't in both 

       as a dictionary of the key and those values

This idea isn't working and obviously highly inefficient. I was hoping there is a more efficient working way to do this

asked Nov 15 '18 at 2:17

Mykel

336

I have question a bit similar to:Replacing the value of a Python dictionary with the value of another dictionary that matches the other dictionaries key

However in my case I got two dictionaries

dict1 = {'foo' : ['val1' , 'val2' , 'val3'] , 'bar' : ['val4' , 'val5']}



dict2 = {'foo' : ['val2', 'val10', 'val11'] , 'bar' : ['val1' , 'val4']}

What I want to return is

dict3 = {'foo' : ['val10', 'val11'] , 'bar' : ['val1']}

and the opposite which is

dict4 = {'foo' : ['val1', 'val3'] , 'bar' : ['val5']}

where dict3 returns a dictionary of the values the keys 'foo' and 'bar' has gained in dict2 and the dict4 is a dictionary of the values the keys 'foo' and 'bar' has lost in dict2

One way I have tried solving this is to:

 iterate over both dictionaries then

    if key of dict1 == key of dict2

       return the values of the key in dict1 and compare with the values in dict2

       return the values that aren't in both 

       as a dictionary of the key and those values

This idea isn't working and obviously highly inefficient. I was hoping there is a more efficient working way to do this

python dictionary

asked Nov 15 '18 at 2:17

Mykel

336

asked Nov 15 '18 at 2:17

Mykel

336

asked Nov 15 '18 at 2:17

Mykel

336

asked Nov 15 '18 at 2:17

Mykel

336

asked Nov 15 '18 at 2:17

Mykel

336

add a comment |

1 Answer
1

active

oldest

votes

Two dict comprehensions will do the trick:

dict3 = {k: [x for x in v if x not in dict1[k]] for k, v in dict2.items()}

print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {k: [x for x in v if x not in dict2[k]] for k, v in dict1.items()}

print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

The above two comprehensions basically filter out the values from key that don't exist in the other dictionary, which is done both ways.

You can also do this without dict comprehensions:

dict3 = {}

for k,v in dict2.items():

    dict3[k] = [x for x in v if x not in dict1[k]]



print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {}

for k,v in dict1.items():

    dict4[k] = [x for x in v if x not in dict2[k]]



print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

edited Nov 15 '18 at 2:41

answered Nov 15 '18 at 2:24

RoadRunner

11.3k31340

Thanks. That was clear and worked. Is there a place I can learn more dict comprehensions?

– Mykel
Nov 15 '18 at 2:36

1

@Mykel You can try following www.datacamp.com/community/tutorials/python-dictionary-comprehension. This is a good tutorial on dictionaries in general, including dict comprehensions. Also note that you don't have to use dict comprehensions, they are just handy for making quick one liners. The above can be easily done without them, it just requires more code.

– RoadRunner
Nov 15 '18 at 2:38

1

I understand that other method requires more code. Dict comprehensions however are very handy and I am hoping to understand more of them. Thanks again

– Mykel
Nov 15 '18 at 2:47

1

@Mykel Yeah, they are very handy. If you understand list comprehensions, they are the same idea, just slightly different syntax. No problem man :).

– RoadRunner
Nov 15 '18 at 2:48

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

Two dict comprehensions will do the trick:

dict3 = {k: [x for x in v if x not in dict1[k]] for k, v in dict2.items()}

print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {k: [x for x in v if x not in dict2[k]] for k, v in dict1.items()}

print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

The above two comprehensions basically filter out the values from key that don't exist in the other dictionary, which is done both ways.

You can also do this without dict comprehensions:

dict3 = {}

for k,v in dict2.items():

    dict3[k] = [x for x in v if x not in dict1[k]]



print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {}

for k,v in dict1.items():

    dict4[k] = [x for x in v if x not in dict2[k]]



print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

edited Nov 15 '18 at 2:41

answered Nov 15 '18 at 2:24

RoadRunner

11.3k31340

Thanks. That was clear and worked. Is there a place I can learn more dict comprehensions?

– Mykel
Nov 15 '18 at 2:36

1

@Mykel You can try following www.datacamp.com/community/tutorials/python-dictionary-comprehension. This is a good tutorial on dictionaries in general, including dict comprehensions. Also note that you don't have to use dict comprehensions, they are just handy for making quick one liners. The above can be easily done without them, it just requires more code.

– RoadRunner
Nov 15 '18 at 2:38

1

I understand that other method requires more code. Dict comprehensions however are very handy and I am hoping to understand more of them. Thanks again

– Mykel
Nov 15 '18 at 2:47

1

@Mykel Yeah, they are very handy. If you understand list comprehensions, they are the same idea, just slightly different syntax. No problem man :).

– RoadRunner
Nov 15 '18 at 2:48

add a comment |

Two dict comprehensions will do the trick:

dict3 = {k: [x for x in v if x not in dict1[k]] for k, v in dict2.items()}

print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {k: [x for x in v if x not in dict2[k]] for k, v in dict1.items()}

print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

The above two comprehensions basically filter out the values from key that don't exist in the other dictionary, which is done both ways.

You can also do this without dict comprehensions:

dict3 = {}

for k,v in dict2.items():

    dict3[k] = [x for x in v if x not in dict1[k]]



print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {}

for k,v in dict1.items():

    dict4[k] = [x for x in v if x not in dict2[k]]



print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

edited Nov 15 '18 at 2:41

answered Nov 15 '18 at 2:24

RoadRunner

11.3k31340

Thanks. That was clear and worked. Is there a place I can learn more dict comprehensions?

– Mykel
Nov 15 '18 at 2:36

1

@Mykel You can try following www.datacamp.com/community/tutorials/python-dictionary-comprehension. This is a good tutorial on dictionaries in general, including dict comprehensions. Also note that you don't have to use dict comprehensions, they are just handy for making quick one liners. The above can be easily done without them, it just requires more code.

– RoadRunner
Nov 15 '18 at 2:38

1

I understand that other method requires more code. Dict comprehensions however are very handy and I am hoping to understand more of them. Thanks again

– Mykel
Nov 15 '18 at 2:47

1

@Mykel Yeah, they are very handy. If you understand list comprehensions, they are the same idea, just slightly different syntax. No problem man :).

– RoadRunner
Nov 15 '18 at 2:48

add a comment |

Two dict comprehensions will do the trick:

dict3 = {k: [x for x in v if x not in dict1[k]] for k, v in dict2.items()}

print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {k: [x for x in v if x not in dict2[k]] for k, v in dict1.items()}

print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

The above two comprehensions basically filter out the values from key that don't exist in the other dictionary, which is done both ways.

You can also do this without dict comprehensions:

dict3 = {}

for k,v in dict2.items():

    dict3[k] = [x for x in v if x not in dict1[k]]



print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {}

for k,v in dict1.items():

    dict4[k] = [x for x in v if x not in dict2[k]]



print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

edited Nov 15 '18 at 2:41

answered Nov 15 '18 at 2:24

RoadRunner

11.3k31340

Two dict comprehensions will do the trick:

dict3 = {k: [x for x in v if x not in dict1[k]] for k, v in dict2.items()}

print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {k: [x for x in v if x not in dict2[k]] for k, v in dict1.items()}

print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

The above two comprehensions basically filter out the values from key that don't exist in the other dictionary, which is done both ways.

You can also do this without dict comprehensions:

dict3 = {}

for k,v in dict2.items():

    dict3[k] = [x for x in v if x not in dict1[k]]



print(dict3)

# {'foo': ['val10', 'val11'], 'bar': ['val1']}



dict4 = {}

for k,v in dict1.items():

    dict4[k] = [x for x in v if x not in dict2[k]]



print(dict4)

# {'foo': ['val1', 'val3'], 'bar': ['val5']}

edited Nov 15 '18 at 2:41

answered Nov 15 '18 at 2:24

RoadRunner

11.3k31340

edited Nov 15 '18 at 2:41

answered Nov 15 '18 at 2:24

RoadRunner

11.3k31340

answered Nov 15 '18 at 2:24

RoadRunner

11.3k31340

answered Nov 15 '18 at 2:24

RoadRunner

11.3k31340

Thanks. That was clear and worked. Is there a place I can learn more dict comprehensions?

– Mykel
Nov 15 '18 at 2:36

1

@Mykel You can try following www.datacamp.com/community/tutorials/python-dictionary-comprehension. This is a good tutorial on dictionaries in general, including dict comprehensions. Also note that you don't have to use dict comprehensions, they are just handy for making quick one liners. The above can be easily done without them, it just requires more code.

– RoadRunner
Nov 15 '18 at 2:38

1

I understand that other method requires more code. Dict comprehensions however are very handy and I am hoping to understand more of them. Thanks again

– Mykel
Nov 15 '18 at 2:47

1

@Mykel Yeah, they are very handy. If you understand list comprehensions, they are the same idea, just slightly different syntax. No problem man :).

– RoadRunner
Nov 15 '18 at 2:48

add a comment |

Thanks. That was clear and worked. Is there a place I can learn more dict comprehensions?

– Mykel
Nov 15 '18 at 2:36

1

@Mykel You can try following www.datacamp.com/community/tutorials/python-dictionary-comprehension. This is a good tutorial on dictionaries in general, including dict comprehensions. Also note that you don't have to use dict comprehensions, they are just handy for making quick one liners. The above can be easily done without them, it just requires more code.

– RoadRunner
Nov 15 '18 at 2:38

1

I understand that other method requires more code. Dict comprehensions however are very handy and I am hoping to understand more of them. Thanks again

– Mykel
Nov 15 '18 at 2:47

1

@Mykel Yeah, they are very handy. If you understand list comprehensions, they are the same idea, just slightly different syntax. No problem man :).

– RoadRunner
Nov 15 '18 at 2:48

Thanks. That was clear and worked. Is there a place I can learn more dict comprehensions?

– Mykel
Nov 15 '18 at 2:36

@Mykel You can try following www.datacamp.com/community/tutorials/python-dictionary-comprehension. This is a good tutorial on dictionaries in general, including dict comprehensions. Also note that you don't have to use dict comprehensions, they are just handy for making quick one liners. The above can be easily done without them, it just requires more code.

– RoadRunner
Nov 15 '18 at 2:38

I understand that other method requires more code. Dict comprehensions however are very handy and I am hoping to understand more of them. Thanks again

– Mykel
Nov 15 '18 at 2:47

@Mykel Yeah, they are very handy. If you understand list comprehensions, they are the same idea, just slightly different syntax. No problem man :).

– RoadRunner
Nov 15 '18 at 2:48

add a comment |

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