CODEWITHSUNDEEP
python-2.7dictionarykey
QM.py
QM.py

Reputation: 652

The variable XXXX is undefined

I'm try to find the biggest value and corresponding key in a dict totals, when I code like this, I can get the right answer:

highest_value = 0
highest_key = None
for a_country in totals.keys():
    if totals[a_country] > highest_value:
        highest_value = totals[a_country]
        highest_key = a_country

while I use another way, an error "The variable highest_key is undefined.". 

highest_value = 0
highest_key = None
for a_country in totals.keys():
        highest_value = totals[a_country] if totals[a_country] > highest_value else highest_value 
        highest_key = a_country if totals[a_country] > highest_value else highest_key

I'm confused... I think the two codes are the same ....

Upvotes: 0

Views: 1297

Answers (1)

Siva Shanmugam
Siva Shanmugam

Reputation: 658

Considered this as totals:

totals={'20':'10','40':'20','60':'30','80':'40','100':'50','120':'60'}

Explanation:

for your first program I got result like,

Value 60 Key 120

The problem with your second code is in the loop, in first program you are obtaining the highest value and assigning corresponding key to it. But in second you have given

highest_key = a_country if totals[a_country] > highest_value else highest_key

i.e. here highest value now is '60'. So there wont be greater value than the 60, so enters into the else and gives the default none as result,

if you change it to == then you will get the corresponding key.

here it is,

totals={'20':'10','40':'20','60':'30','80':'40','100':'50','120':'60'}
highest_value = 0
highest_key = None
for a_country in totals.keys():
    print a_country
        highest_value = totals[a_country] if totals[a_country] > highest_value else highest_value 
        highest_key = a_country if totals[a_country] == highest_value else highest_key
print "Value",highest_value
print "Key",highest_key

Result is,

Value 60 Key 120

Upvotes: 1

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