Py Pandas .format(dataframe)

问题

As Python newbie I recently discovered that with Py 2.7 I can do something like:

print '{:20,.2f}'.format(123456789)

which will give the resulting output:

123,456,789.00

I'm now looking to have a similar outcome for a pandas df so my code was like:

import pandas as pd
import random
data = [[random.random()*10000 for i in range(1,4)] for j in range (1,8)]
df = pd.DataFrame (data)
print '{:20,.2f}'.format(df)

In this case I have the error:

 Unknown format code 'f' for object of type 'str'

Any suggestions to perform something like '{:20,.2f}'.format(df) ?

As now my idea is to index the dataframe (it's a small one), then format each individual float within it, might be assign astype(str), and rebuild the DF ... but looks so looks ugly :-( and I'm not even sure it'll work ..

What do you think ? I'm stuck ... and would like to have a better format for my dataframes when these are converted to reportlabs grids.

回答1:

import pandas as pd
import numpy as np
data = np.random.random((8,3))*10000
df = pd.DataFrame (data)
pd.options.display.float_format = '{:20,.2f}'.format
print(df)

yields (random output similar to)

                     0                    1                    2
0             4,839.01             6,170.02               301.63
1             4,411.23             8,374.36             7,336.41
2             4,193.40             2,741.63             7,834.42
3             3,888.27             3,441.57             9,288.64
4               220.13             6,646.20             3,274.39
5             3,885.71             9,942.91             2,265.95
6             3,448.75             3,900.28             6,053.93

The docstring for pd.set_option or pd.describe_option explains:

display.float_format: [default: None] [currently: None] : callable
        The callable should accept a floating point number and return
        a string with the desired format of the number. This is used
        in some places like SeriesFormatter.
        See core.format.EngFormatter for an example.

来源：https://stackoverflow.com/questions/18404946/py-pandas-formatdataframe

标签

python

format

pandas

dataframe