python - 字典中有多个相同的键

Question

this is my code

#this is for the max Day of a month, without leap year 
day_month = {'Janauary': 31, 'February':28, 'March':31, 'April':30, 'May':31, 'June':30, 'July':31, 'August':31, 'September':30, 'October':31, 'November':30, 'December':31}
#this dict i get as Input
myCalendar = {'April':30, 'July':10, 'May':20, 'February':29, 'August':31, 'August':13, 'August':21}
#this is the desired month to work with
month = 'August'

print(month in myCalendar) # it shows that month exists in myCalendar  
print(myCalendar[month]) # this give the value
print('')

for i in myCalendar:
    print(str(i) + ' ' + str(myCalendar[i]))

these are the output

True
21

#result of for loop
April 30
July 10
May 20
February 29
August 21  #the problem is this one, I want to have the max value of those three values

for August I have {'August':31, 'August':13, 'August':21} what I would like to have is the max Value 'August':31 or better {'August': [13,21,31]}

I know that in Python Dict only accepts one identical key

not allowed to use packages/libraries

can i use class?

thanks

Answer 1

what I would like to have is the max Value

to handle those types of collisions you would first check to see if the key already exists

if month in myCalender.keys():

if it does exist you would redeclare it with the max of both the inputs

myCalender[month] = max(myCalender[month], day_month[month] )

or better {'August': [13,21,31]}

to do this you would do the same as above to check whether or the key already exists

if it does you would then append the new value to the list inside the dict

myCalender[month] = list(myCalender[month]).append(day_calender[month])

Answer 2

Here is one way of representing your data so that it is legal Python code that preserves all of the original data:

myCalendar = [('April', 30), ('July',10), ('May',20), ('February',29), ('August', 31), ( 'August', 13), ('August', 21)]

If you do that, you can then produce the structure you want with the following code:

myCalendar = [('April', 30), ('July',10), ('May',20), ('February',29), ('August', 31), ( 'August', 13), ('August', 21)]

myIndex = {}
for k, v in myCalendar:
    if k not in myIndex:
        myIndex[k] = []
    myIndex[k].append(v)

print(myIndex)

Result:

{'April': [30], 'July': [10], 'May': [20], 'February': [29], 'August': [31, 13, 21]}