CODEWITHSUNDEEP
pythonlistdictionaryfor-loopnested
Parul Joshi
Parul Joshi

Reputation: 11

how to print the list value of the nested dictionary

I have created the following dictionary:

Book_list={
 'Fiction': {1001: ['Pride and Prejudice', 'available'],
             1002: ['Fahrenheit 451', 'available']},
 'Horror': {2001: ['House of leaves', 'available'],
            2002: ['The Shinking', 'available']}}

now I want to store the status that is "available" in a variable with its key so that it can be used further for delete or update.

So the output I mean is like:

status={1001:available,1002:available,2001:available,2002:available}

Please help me by telling that how could I get this output.

Upvotes: 0

Views: 120

Answers (4)

Kondapalli Lavanya
Kondapalli Lavanya

Reputation: 1

With this code you get almost exactly the output you want:

d={}
for a in Book_list.values():
    for x,y in a.items():
        d[x]=y[1]
print("status=", d)

You could also, of course, assign d to your a status variable.

This code just creates first an empty d as dict and then fills it with data and finally prints it. To fill d with data, a, x and y take different values while walking (iterating) over your object:

  • a: For example {1001: ['Pride and Prejudice', 'available'], 1002: ['Fahrenheit 451', 'available']}
  • x: For example 1001
  • y: For example ['Pride and Prejudice', 'available']
    • y[1] would then be 'available'

Upvotes: 0

no comment
no comment

Reputation: 10592

Using Python 3.10's structural pattern matching, maybe not super appropriate/helpful for this, but I just wanted to try it :-)

rs = {}
for category in Book_list.values():
    for item in category.items():
        match item:
            case ii, [_, 'available' as status]:
                rs[ii] = status

(code adapted from Dani's)

Upvotes: 0

Dani Mesejo
Dani Mesejo

Reputation: 61930

One approach is to use a dictionary comprehension:

rs = {ii : status for category in Book_list.values()  for ii, (name, status) in category.items() if status == "available"}
print(rs)

Output

{1001: 'available', 1002: 'available', 2001: 'available', 2002: 'available'}

The above is equivalent to the followings nested for loops:

for category in Book_list.values():
    for ii, (name, status) in category.items():
        if status == "available":
            rs[ii] = status

For understanding the unpacking expressions such as:

# _, category
# ii, (name, status)

you could read this link. For a general introduction to Python's data structures I suggest reading the documentation.

Upvotes: 3

ibrahim koz
ibrahim koz

Reputation: 629

def receive_available_books(Book_list):
    status = {}
    for cat in Book_list.values():
        for code, book  in cat.items():
            status[code] = book[1]
    return status

Output: {1001: 'available', 1002: 'available', 2001: 'available', 2002: 'available'}

Upvotes: 0

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