to_html formatter not called for float values in a mixed-type column

[patricksurry]

When column x has float64 type, the custom formatter is applied to every value

t = pd.DataFrame([[0], [10.4], [3]], columns=['x'])
display(HTML(t.to_html(formatters=dict(x='xxx'.format))))

   x
------
0  xxx
1  xxx
2  xxx

But when column x is mixed type, the formatter isn't called for (only) floating point values

t = pd.DataFrame([['a'], [0], [10.4], [3]], columns=['x'])
display(HTML(t.to_html(formatters=dict(x='xxx'.format))))

   x
------
0  xxx
1  xxx
2  10.4
3  xxx

output of pd.show_versions()

INSTALLED VERSIONS

commit: None
python: 2.7.11.final.0
python-bits: 64
OS: Darwin
OS-release: 14.5.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.18.0
nose: None
pip: 1.5.4
setuptools: 20.7.0
Cython: None
numpy: 1.11.0
scipy: 0.17.0
statsmodels: None
xarray: None
IPython: 4.1.2
sphinx: None
patsy: None
dateutil: 2.4.2
pytz: 2016.3
blosc: None
bottleneck: None
tables: 3.2.2
numexpr: 2.5.2
matplotlib: 1.5.1
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: 1.0.12
pymysql: None
psycopg2: None
jinja2: None
boto: None

[jreback]

what exactly are you expecting here?

[patricksurry]

I'm expecting it to call my format function for each value in the column. It doesn't seem to call the formatter at all. Obviously 'xxx'.format is a stupid example - but it illustrates that it's not applying the function to the 10.4 value when it occurs in a mixed-type column. A more realistic formatter would be something like lambda x: x if type(x) is str else '${:,.0f}'.format(x) which displays:

    x
0   a
1   $0
2   10.4
3   $3

when I'd expect $10 for the 3rd row.

[jreback]

how so? show an expected result (with and w/o object columns)

[patricksurry]

def f(x):
    return x if type(x) is str else '${:,.0f}'.format(x)

t = pd.DataFrame([['a'], [0], [10.4], [3]], columns=['x'])
display(HTML(t.to_html(formatters=dict(x=f))))

produces

    x
0   a
1   $0
2   10.4
3   $3

instead of what I expected:

    x
0   a
1   $0
2   $10
3   $3

or am I missing something? (the 'xxx'.format in my example was just to illustrate that it doesn't call my function at all for the 10.4 value)

[patricksurry]

If instead you create the data frame without the 'a' row, so the column type is float64, you get the expected result:

t = pd.DataFrame([[0], [10.4], [3]], columns=['x'])
display(HTML(t.to_html(formatters=dict(x=f))))

    x
0   $0
1   $10
2   $3

[jobevers]

This is still an issue in 0.21.1

INSTALLED VERSIONS

commit: None
python: 3.5.2.final.0
python-bits: 64
OS: Linux
OS-release: 4.10.0-42-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.21.1
pytest: 3.0.7
pip: 9.0.1
setuptools: 36.0.1
Cython: None
numpy: 1.13.3
scipy: 1.0.0
pyarrow: None
xarray: None
IPython: 6.1.0
sphinx: 1.6.3
patsy: None
dateutil: 2.6.1
pytz: 2017.3
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: 1.5.3
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.5.3
html5lib: 0.999999999
sqlalchemy: 1.1.4
pymysql: 0.7.11.None
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None

[jreback]

@jobevers hence the open status

[franz101]

Also having problems with formatters