CODEWITHSUNDEEP
python
Geoffrey Seamons
Geoffrey Seamons

Reputation: 1

Unsupported operant type(s) for -: ‘float’ and ‘str’

I have been working on a project and I thought I had an understanding of how to manipulate information in a dictionary into a float to use for comparison however I can see that that is not the case. Any suggestions? 

country = "France"
url = 'https://covid-api.mmediagroup.fr/v1/history?country='+country+'&status=confirmed'
print(url)
request = requests.get(url)
dct1 = json.loads(request.text)

key1 = "All"
key2 = "dates"
#datekey = specific date

confirmedcases = []
for datekey in dct1[key1][key2]:
    confirmedcases.append(float(dct1[key1][key2][datekey]))
    confirmedcases.append(datekey)
    
confirmedcases.reverse()
print(confirmedcases)


current_high = 0
new_cases = []
for i in range(1,len(confirmedcases)):
    new_cases.append(float(confirmedcases[i]) - (float(confirmedcases[i-1])))
    if confirmedcases[i] - confirmedcases[i-1] > current_high:
        current_high = confirmedcases[i] - confirmedcases[i-1]
        dct1 = dct1[i]
        
print(current_high)
input("press any key")

Upvotes: 0

Views: 66

Answers (2)

Dattaprasad Ekavade
Dattaprasad Ekavade

Reputation: 128

For Comparison, floats may not be that optimal, as it can get bit complicated to handle.

If possible, try to use Integers, if the dataset you receive contains the number of cases. (if any decimal values in them are not significant)

Else, can follow up on this solution to get an idea of how to go about comparisons with floats.

https://stackoverflow.com/a/5595453/8495683

Upvotes: 0

mozway
mozway

Reputation: 260630

The error raised is :

ValueError                                Traceback (most recent call last)
<ipython-input-1043-c9ba12594a26> in <module>
     22 new_cases = []
     23 for i in range(1,len(confirmedcases)):
---> 24     new_cases.append(float(confirmedcases[i]) - (float(confirmedcases[i-1])))
     25     if confirmedcases[i] - confirmedcases[i-1] > current_high:
     26         current_high = confirmedcases[i] - confirmedcases[i-1]

ValueError: could not convert string to float: '2020-01-22'

Indeed, confirmedcases[i-1] is '2020-01-22' that cannot be converted to float.

How did this happen? Let's look at confirmedcases:

['2020-01-22', 0.0, '2020-01-23', 0.0, '2020-01-24', 2.0, '2020-01-25', 3.0, ...]

This is likely not correct to have mixed the dates and values.

This happened in a previous block:

confirmedcases = []
for datekey in dct1[key1][key2]:
    confirmedcases.append(float(dct1[key1][key2][datekey]))
    confirmedcases.append(datekey) # why is the date added?

There are other issues in the code, but this gives you a good starting point to debug it.

Upvotes: 2

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