CODEWITHSUNDEEP
pythonpandas
MaxB
MaxB

Reputation: 458

Convert string of floats to list of rounded floats

I am trying to convert a column from string to float. The df column looks something like below. Some rows have no numbers in them, but are a space ' '.

    col
'1.1, 1.0006'
    '  '

I am trying to round each number to the third decimal place. The output would look something like this. 

    col
'1.100, 1.001'
    '  '

My thinking:

df['col'] = df['col'].astype(float)
df['col'] = df['col'].round(3)

Upvotes: 1

Views: 273

Answers (3)

Loochie
Loochie

Reputation: 2472

Well you can try this:

df['col'] = df['col'].apply(lambda x: x.split(', '))
def string_to_float(list):
    x = []
    for each in list:
        x.append(round(float(each), 3))
    return x
df['col'] = df['col'].apply(lambda x: string_to_float(x))

UPDATE: The following code will work perfectly now:

df['col'] = df['col'].apply(lambda x: x.replace("'", "").replace(" ", "").split(','))
def string_to_float(list):
    x = []
    for each in list:
        if each != '':
            x.append((str(round(float(each), 3))))
    return ','.join(x)
df['col'] = df['col'].apply(lambda x: string_to_float(x))

Upvotes: 1

Chris Adams
Chris Adams

Reputation: 18647

Try:

def fix_string(string):
    numbers = pd.to_numeric(string.split(','), errors='coerce').round(3)
    return numbers

df['col'] = df['col'].apply(fix_string)

Upvotes: 1

jezrael
jezrael

Reputation: 862731

I think you need:

df = pd.DataFrame({'col':["'1.1, 1.0006'", "'   '"]})
print (df)

def func(x):
    out = []
    #split and strip values, try convert each value to float, if error, get original value
    for y in x.strip("'").split(', '):
        try:
            out.append(round(float(y), 3))
        except:
            out.append(y)

    return (out)

df['new'] = df['col'].apply(func)
print (df)
             col           new
0  '1.1, 1.0006'  [1.1, 1.001]
1          '   '         [   ]

If need strings from floats use f-strings:

def func(x):
    out = []
    for y in x.strip("'").split(', '):
        try:
            out.append(f'{round(float(y), 3):.3f}')
        except:
            out.append(y)

    return (out)

df['new'] = df['col'].apply(func)
print (df)

             col             new
0  '1.1, 1.0006'  [1.100, 1.001]
1          '   '           [   ]

And for strings add join to end:

def func(x):
    out = []
    for y in x.strip("'").split(', '):
        try:
            out.append(f'{round(float(y), 3):.3f}')
        except:
            out.append(y)

    return (', '.join(out))

df['new'] = df['col'].apply(func)
print (df)
             col           new
0  '1.1, 1.0006'  1.100, 1.001
1          '   '

Upvotes: 2

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