bug in to_html() with formatters=<list> and max_cols

[simonjayhawkins]

Code Sample, a copy-pastable example if possible

import pandas as pd
import pandas.util.testing as tm
df = tm.makeDataFrame()[:5]
fmt = lambda x: str(x)+'_mod'
formatters=[fmt,fmt,None,None]
print(df.to_html(formatters=formatters))
print(df.to_html(formatters=formatters, max_cols=3))

	A	B	C	D
auVRHDVXKo	0.8480611318869997_mod	2.4785562034246165_mod	-1.258639	1.134326
4IL8N5I4tk	-0.4349431395826644_mod	1.491615558543841_mod	-1.392170	-1.119832
PACjyGDGOG	-0.8963777799744853_mod	0.5011278874888623_mod	-0.475899	1.041362
dGFzef3Sbf	0.2615536705949168_mod	1.4994356591304039_mod	0.713050	-0.613034
U2mGzTnuUi	-0.8803411110313392_mod	-0.5522186462569404_mod	0.309005	-1.715071

	A	...	D
auVRHDVXKo	0.8480611318869997_mod	...	1.134326092661258_mod
4IL8N5I4tk	-0.4349431395826644_mod	...	-1.1198318989339953_mod
PACjyGDGOG	-0.8963777799744853_mod	...	1.0413616487242832_mod
dGFzef3Sbf	0.2615536705949168_mod	...	-0.6130344240242487_mod
U2mGzTnuUi	-0.8803411110313392_mod	...	-1.7150707649504604_mod

Problem description

When a list of formatters is given, the integer position of the truncated dataframe is used to lookup the formatter.

the same problem also occurs for to_string()

Expected Output

	A	...	D
auVRHDVXKo	0.8480611318869997_mod	...	1.134326
4IL8N5I4tk	-0.4349431395826644_mod	...	-1.119832
PACjyGDGOG	-0.8963777799744853_mod	...	1.041362
dGFzef3Sbf	0.2615536705949168_mod	...	-0.613034
U2mGzTnuUi	-0.8803411110313392_mod	...	-1.715071

Output of pd.show_versions()

INSTALLED VERSIONS

commit: None
python: 3.7.2.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 58 Stepping 9, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.25.0.dev0+348.gb727c6b32
pytest: 4.3.0
pip: 19.0.3
setuptools: 40.6.3
Cython: 0.29.5
numpy: 1.16.2
scipy: 1.2.1
pyarrow: 0.11.1
xarray: 0.11.3
IPython: 7.3.0
sphinx: 1.8.4
patsy: 0.5.1
dateutil: 2.8.0
pytz: 2018.9
blosc: None
bottleneck: 1.2.1
tables: 3.4.4
numexpr: 2.6.9
feather: None
matplotlib: 3.0.2
openpyxl: 2.6.0
xlrd: 1.2.0
xlwt: 1.3.0
xlsxwriter: 1.1.5
lxml.etree: 4.3.1
bs4: 4.7.1
html5lib: 1.0.1
sqlalchemy: 1.2.18
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: 0.2.0
fastparquet: 0.2.1
pandas_gbq: None
pandas_datareader: None
gcsfs: None

[simonjayhawkins]

Would this be an issue that I could attempt to work on?

go for it!

I would be a first time contributor, but none of the good-first-issue posts are available at the moment.

i would recommend #23922