Hi, For illustration purpose, I'll assume the following dataset: ``` python In [1]: d=pd.DataFrame({'col1':[9.999e-8, 1e-7, 1.0001e-7, 2e-7, 4.999e-7, 5e-7, 5.0001e-7, 6e-7]}) In [2]: d Out[2]: col1 0 9.999000e-08 1 1.000000e-07 2 1.000100e-07 3 2.000000e-07 4 4.999000e-07 5 5.000000e-07 6 5.000100e-07 7 6.000000e-07 ``` I've noticed the following behavior (in pandas 0.16 and 0.15.2): 1) When values from range [1e-7, 5e-7] are displayed along with values that are less than 1e-7, the output is OK: ``` python In [3]: d[0:6] Out[3]: col1 0 9.999000e-08 1 1.000000e-07 2 1.000100e-07 3 2.000000e-07 4 4.999000e-07 5 5.000000e-07 ``` 2) When values exclusively from that range are displayed, the output is 0: ``` python In [4]: d[1:6] Out[4]: col1 1 0 2 0 3 0 4 0 5 0 ``` 3) When values from that range are displayed along with values greater than 5e-7, the output for them is 0.000000: ``` python In [5]: d[1:8] Out[5]: col1 1 0.000000 2 0.000000 3 0.000000 4 0.000000 5 0.000000 6 0.000001 7 0.000001 ``` I'm assuming it's a rounding / output formatting error. Also: ``` python In [6]: pd.show_versions() INSTALLED VERSIONS ------------------ commit: None python: 3.4.2.final.0 python-bits: 64 OS: Linux OS-release: 2.6.32-431.el6.x86_64 machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_US.UTF-8 pandas: 0.16.0 nose: 1.3.4 Cython: 0.21.2 numpy: 1.9.2 scipy: 0.14.0 statsmodels: 0.6.1 IPython: 2.3.1 sphinx: None patsy: 0.3.0 dateutil: 2.4.1 pytz: 2015.2 bottleneck: None tables: None numexpr: None matplotlib: 1.4.2 openpyxl: None xlrd: None xlwt: None xlsxwriter: None lxml: None bs4: None html5lib: None httplib2: None apiclient: None sqlalchemy: None pymysql: None psycopg2: None ```