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2

I have two dictionaries, and I want to compare them and see what is different between the two. Where I am getting confused is the dict. Is there a name for this?

Everything is working fine, I just don't really understand why it works or what it is doing.

x = "#04": 0, "#05": 0, "#07": 0, "#08": 1, "#09": 0, "#10": 0, "#11": 1, "#12": 1, "#14": 1, "#15": 1, "#17": 0, "#18": 1, "#19": 1, "#20": 1

y = "#04": 1, "#05": 0, "#07": 0, "#08": 1, "#09": 0, "#10": 0, "#11": 1, "#12": 1, "#14": 1, "#15": 0, "#17": 1, "#18": 1, "#19": 0, "#20": 1

dict = k: x[k] for k in x if y[k] != x[k]

list = []

for k, v in dict.items()
 if v==0:
 difference = k + ' became ' + '0'
 list.append(difference)
 else:
 difference = k + ' became ' + '1'
 list.append(difference)

print(list)

It should print ['#04 became 0', '#15 became 1', '#17 became 0', '#19 became 1'] but I don't understand how the dict works to loop through the x and y dictionaries.

python dictionary

share|improve this question

edited Mar 27 at 4:33

Life is complex

87766 silver badges1818 bronze badges

asked Mar 27 at 1:27

chummysparrowchummysparrow

1322 bronze badges

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  It is called "dictionary comprehension", look it up. Also don't use variable names such as dict and list as they will mask the built-in names.
  
  – Selcuk
  Mar 27 at 1:30
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  dict is a built-in, you should not use it as a variable.
  
  – dcg
  Mar 27 at 1:30
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Possible duplicate of Dictionary Comprehension in Python 3
  
  – AkshayNevrekar
  Mar 27 at 4:38
  

  
  
  
  

add a comment | 

2

I have two dictionaries, and I want to compare them and see what is different between the two. Where I am getting confused is the dict. Is there a name for this?

Everything is working fine, I just don't really understand why it works or what it is doing.

x = "#04": 0, "#05": 0, "#07": 0, "#08": 1, "#09": 0, "#10": 0, "#11": 1, "#12": 1, "#14": 1, "#15": 1, "#17": 0, "#18": 1, "#19": 1, "#20": 1

y = "#04": 1, "#05": 0, "#07": 0, "#08": 1, "#09": 0, "#10": 0, "#11": 1, "#12": 1, "#14": 1, "#15": 0, "#17": 1, "#18": 1, "#19": 0, "#20": 1

dict = k: x[k] for k in x if y[k] != x[k]

list = []

for k, v in dict.items()
 if v==0:
 difference = k + ' became ' + '0'
 list.append(difference)
 else:
 difference = k + ' became ' + '1'
 list.append(difference)

print(list)

It should print ['#04 became 0', '#15 became 1', '#17 became 0', '#19 became 1'] but I don't understand how the dict works to loop through the x and y dictionaries.

python dictionary

share|improve this question

edited Mar 27 at 4:33

Life is complex

87766 silver badges1818 bronze badges

asked Mar 27 at 1:27

chummysparrowchummysparrow

1322 bronze badges

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  It is called "dictionary comprehension", look it up. Also don't use variable names such as dict and list as they will mask the built-in names.
  
  – Selcuk
  Mar 27 at 1:30
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  dict is a built-in, you should not use it as a variable.
  
  – dcg
  Mar 27 at 1:30
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Possible duplicate of Dictionary Comprehension in Python 3
  
  – AkshayNevrekar
  Mar 27 at 4:38
  

  
  
  
  

add a comment | 

I have two dictionaries, and I want to compare them and see what is different between the two. Where I am getting confused is the dict. Is there a name for this?

Everything is working fine, I just don't really understand why it works or what it is doing.

x = "#04": 0, "#05": 0, "#07": 0, "#08": 1, "#09": 0, "#10": 0, "#11": 1, "#12": 1, "#14": 1, "#15": 1, "#17": 0, "#18": 1, "#19": 1, "#20": 1

y = "#04": 1, "#05": 0, "#07": 0, "#08": 1, "#09": 0, "#10": 0, "#11": 1, "#12": 1, "#14": 1, "#15": 0, "#17": 1, "#18": 1, "#19": 0, "#20": 1

dict = k: x[k] for k in x if y[k] != x[k]

list = []

for k, v in dict.items()
 if v==0:
 difference = k + ' became ' + '0'
 list.append(difference)
 else:
 difference = k + ' became ' + '1'
 list.append(difference)

print(list)

It should print ['#04 became 0', '#15 became 1', '#17 became 0', '#19 became 1'] but I don't understand how the dict works to loop through the x and y dictionaries.

python dictionary

share|improve this question

edited Mar 27 at 4:33

Life is complex

87766 silver badges1818 bronze badges

asked Mar 27 at 1:27

chummysparrowchummysparrow

1322 bronze badges

x = "#04": 0, "#05": 0, "#07": 0, "#08": 1, "#09": 0, "#10": 0, "#11": 1, "#12": 1, "#14": 1, "#15": 1, "#17": 0, "#18": 1, "#19": 1, "#20": 1

y = "#04": 1, "#05": 0, "#07": 0, "#08": 1, "#09": 0, "#10": 0, "#11": 1, "#12": 1, "#14": 1, "#15": 0, "#17": 1, "#18": 1, "#19": 0, "#20": 1

dict = k: x[k] for k in x if y[k] != x[k]

list = []

for k, v in dict.items()
 if v==0:
 difference = k + ' became ' + '0'
 list.append(difference)
 else:
 difference = k + ' became ' + '1'
 list.append(difference)

print(list)

share|improve this question

edited Mar 27 at 4:33

Life is complex

87766 silver badges1818 bronze badges

asked Mar 27 at 1:27

chummysparrowchummysparrow

1322 bronze badges

share|improve this question

edited Mar 27 at 4:33

Life is complex

87766 silver badges1818 bronze badges

asked Mar 27 at 1:27

chummysparrowchummysparrow

1322 bronze badges

edited Mar 27 at 4:33

Life is complex

87766 silver badges1818 bronze badges

edited Mar 27 at 4:33

Life is complex

87766 silver badges1818 bronze badges

asked Mar 27 at 1:27

chummysparrowchummysparrow

1322 bronze badges

asked Mar 27 at 1:27

chummysparrowchummysparrow

1322 bronze badges

1 Answer
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1

The procedure implemented is comparing two dictionaries assuming that both have the same keys (potentially y could have more entries).

To make this comparison quick, and facilitate the next code block, they decided to generate a dictionary that only contains the keys that have different values.

To generate such dictionary, they use a "dictionary comprehension", which is very efficient.

Now, this construct:

d = k: x[k] for k in x if y[k] != x[k]

can be rewritten as:

d = 
for k,v in x: # for each key->value pairs in dictionary x
 if y[k] != x[k]: # if the corresponding elements are different
 d[k] = x[k] # store the key->value pair in the new dictionary

You could replace x[k] with v above.

share|improve this answer

answered Mar 27 at 5:09

salsal

2,00911 gold badge55 silver badges1515 bronze badges

add a comment | 

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1

The procedure implemented is comparing two dictionaries assuming that both have the same keys (potentially y could have more entries).

To make this comparison quick, and facilitate the next code block, they decided to generate a dictionary that only contains the keys that have different values.

To generate such dictionary, they use a "dictionary comprehension", which is very efficient.

Now, this construct:

d = k: x[k] for k in x if y[k] != x[k]

can be rewritten as:

d = 
for k,v in x: # for each key->value pairs in dictionary x
 if y[k] != x[k]: # if the corresponding elements are different
 d[k] = x[k] # store the key->value pair in the new dictionary

You could replace x[k] with v above.

share|improve this answer

answered Mar 27 at 5:09

salsal

2,00911 gold badge55 silver badges1515 bronze badges

add a comment | 

1

The procedure implemented is comparing two dictionaries assuming that both have the same keys (potentially y could have more entries).

To make this comparison quick, and facilitate the next code block, they decided to generate a dictionary that only contains the keys that have different values.

To generate such dictionary, they use a "dictionary comprehension", which is very efficient.

Now, this construct:

d = k: x[k] for k in x if y[k] != x[k]

can be rewritten as:

d = 
for k,v in x: # for each key->value pairs in dictionary x
 if y[k] != x[k]: # if the corresponding elements are different
 d[k] = x[k] # store the key->value pair in the new dictionary

You could replace x[k] with v above.

share|improve this answer

answered Mar 27 at 5:09

salsal

2,00911 gold badge55 silver badges1515 bronze badges

add a comment | 

The procedure implemented is comparing two dictionaries assuming that both have the same keys (potentially y could have more entries).

To make this comparison quick, and facilitate the next code block, they decided to generate a dictionary that only contains the keys that have different values.

To generate such dictionary, they use a "dictionary comprehension", which is very efficient.

Now, this construct:

d = k: x[k] for k in x if y[k] != x[k]

can be rewritten as:

d = 
for k,v in x: # for each key->value pairs in dictionary x
 if y[k] != x[k]: # if the corresponding elements are different
 d[k] = x[k] # store the key->value pair in the new dictionary

You could replace x[k] with v above.

share|improve this answer

answered Mar 27 at 5:09

salsal

2,00911 gold badge55 silver badges1515 bronze badges

d = k: x[k] for k in x if y[k] != x[k]

d = 
for k,v in x: # for each key->value pairs in dictionary x
 if y[k] != x[k]: # if the corresponding elements are different
 d[k] = x[k] # store the key->value pair in the new dictionary

share|improve this answer

answered Mar 27 at 5:09

salsal

2,00911 gold badge55 silver badges1515 bronze badges

answered Mar 27 at 5:09

salsal

2,00911 gold badge55 silver badges1515 bronze badges

answered Mar 27 at 5:09

salsal

2,00911 gold badge55 silver badges1515 bronze badges