find the elements of a list in the values of a dictionary and accordingly print the key in tabular f-CodePudding

I have this list:

list1 = ['float', 'x', 'b', 'a', '*', ' ', '=', '50']

and this dictionary:

combined_dict = {
    'Keyword': ['float', 'int', 'char'],
    'Identifier': ['x', 'b', 'a', 'p', 'n'],
    'Operator': ['*', ' ', '=', '-', '/'],
    'Constant': ['50', '100', '20']
}

The output should be like:

|list    | Type       |
|:------:|:----------:|
|float   | Keyword    |
| x      | Identifier |
| b      | Identifier |
| a      | Identifier |
| *      | Operator   |
|        | Operator   |
| =      | Operator   |
| 50     | Constant   |

So the goal here is to find the elements of list1 in the values of the dictionary and print the corresponding key. This should be in tabular form as shown.

eg : float from the list is a key of Keyword in the dictiornary.

I wasn't really able to design a loop for this!

CodePudding user response：

You're having trouble because your dictionary is backwards. Dictionaries are made to look up keys mapped to values, not the other way around. So transform your dictionary first:

lookup_dict = {v: k for k, vals in combined_dict.items() for v in vals}

Now the task is trivial:

for s in list1:
    print(f'| {s:06s} | {lookup_dict[s]:10s} |')

I think you can figure out how to print the header and footer in the table.

CodePudding user response：

you could do:

import pandas as pd
combined_dict={'Keyword': ['float','int','char'], 'Identifier': ['x', 'b', 'a','p','n'], 'Operator': ['*', ' ', '=','-','/'], 'Constant': ['50','100','20']}
list1=['float', 'x', 'b', 'a', '*', ' ', '=', '50'] 
types = []
for fromlistvalue in list1:
    for value in combined_dict:
        if fromlistvalue in combined_dict[value]:
            types.append(value)
df = pd.DataFrame({"list":list1,"Type":types})

CodePudding user response：

Lots of code. For the pretty-printing, a for loop might have been more readable.

# transform combined_dict, to allow lookup by token from list1
lookup = dict(sum((
    [(e, key) for e in value]
    for key, value in combined_dict.items()
), []))

# create list with tokens mapped to their corresponding type
mapped = [(key, lookup[key]) for key in list1]

# making it pretty

# column widths for the table based on longest cell in column
width_list = max((len(elem) for elem in list1))
width_type = max((len(t) for _, t in mapped))

# convert mapped tokens into printable rows
converted = ["|{}|{}|".format(
    i.ljust(width_list), t.ljust(width_type)) for i, t in mapped]

# prepare header and divider of table
header = "|{}|{}|".format(
    "list".ljust(width_list), "type".ljust(width_type))
divider = "| {} | {} |".format(
    "-" * (width_list - 2), "-" * (width_type - 2))

# merge all table lines into single string and print
print("\n".join([header, divider]   converted))