CODEWITHSUNDEEP
pythondecimalscientific-notation
Zak Stucke
Zak Stucke

Reputation: 452

How to avoid scientific notation when using databases containing decimal datatype

I have a large dictionary which contains lots of the decimal data type. Many of these values are very small and when printed are displayed in scientific notation. How do I get the dictionary to print as a normal decimal without printing each piece of data individually? Thanks

from decimal import Decimal 

dic = {'value1': Decimal('0.000000123'), 'value2' : Decimal('0.00000001'),
       'value3' : Decimal('0.00000000000001')}

# This happens which I don't want: 
print(dic)
>> {'value1': Decimal('1.23E-7'), 'value2': Decimal('1E-8'), 
    'value3': Decimal('1E-14')}

# I want: 
print(dic)
>> {'value1': Decimal('0.000000123'), 'value2' : Decimal('0.00000001'), 
    'value3' : Decimal('0.00000000000001')}

I cannot use {0:.8f}.format(val) or anything like that on each item individually as there are thousands of items so how can I get values to print without scientific notation? Maybe on creation of the decimal? Thanks

Edit: there are also other datatypes in the dictionary such as strings so a solution cannot be affected by this.

Upvotes: 0

Views: 486

Answers (1)

sacuL
sacuL

Reputation: 51395

If it's really just for looking at your values, then you can do something like this:

import numbers

# Include isinstance() to check that your value is numeric
print(['{}: {:.14f}'.format(k,i) for k,i in dic.items() 
        if isinstance(i, numbers.Number)])

Which returns:

['value1: 0.00000012300000', 'value2: 0.00000001000000', 'value3: 0.00000000000001']

Or, if you still want to print non-numeric values (just not formatted), use:

print(['{}: {:.14f}'.format(k,i) if isinstance(i, numbers.Number) 
        else '{}: {}'.format(k,i) for k,i in dic.items()])

Example:

dic = {'value1': Decimal('0.000000123'), 'value2' : Decimal('0.00000001'),
       'value3' : Decimal('0.00000000000001'), 'value4': 'string'}

print(['{}: {:.14f}'.format(k,i) if isinstance(i, numbers.Number) 
        else '{}: {}'.format(k,i) for k,i in dic.items()])

returns:

['value1: 0.00000012300000', 'value2: 0.00000001000000', 'value3: 0.00000000000001', 'value4: string']

But as you noted, this is only good for viewing your values, as they are returned as strings of your keys and values combined.

Note: I used {:.14f} because your smallest decimal was on the order of E-14

Upvotes: 2

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