columns] Additionally, the method argument to interpolate has been expanded to include ’nearest’, ’zero’, ’slinear’, ’quadratic’, ’cubic’, ’barycentric’, ’krogh’, ’piecewise_polynomial’, ’pchip’, ‘polynomial‘ 1 b 2 2 NaN 3 3 NaN 4 [4 rows x 2 columns] to replace all occurrences of the string ’.’ with zero or more instances of surrounding whitespace with NaN. Regular string replacement still works as expected [24]: converted = np.asarray(rng, dtype=object) In [25]: converted[5] Out[25]: 947116800000000000L Trust me: don’t panic. If you are using NumPy 1.6 and restrict your interaction with datetime64 values to

analysis toolkit, Release 0.17.0 • Bug where pd.read_gbq throws ValueError when Bigquery returns zero rows (GH10273) • Bug in to_json which was causing segmentation fault when serializing 0-rank ndarray now accepts datetime64 as value input. (GH9054) • Allow timedelta string conversion when leading zero is missing from time definition, ie 0:00:00 vs 00:00:00. (GH9570) 1.3. v0.16.1 (May 11, 2015) 37 indices are no longer mutated. (GH9542) • Bug in json serialization causing a segfault when a frame had zero length. (GH9805) • Bug in read_csv where missing trailing delimiters would cause segfault. (GH5664)

(GH7542) • Bug in rolling_count() and expanding_*() functions unnecessarily producing error message for zero-length data (GH8056) • Bug in rolling_apply() and expanding_apply() interpreting min_periods=0 as clip long column data (GH8305) • Bug in DataFrame terminal display: Setting max_column/max_rows to zero did not trigger auto-resizing of dfs to fit terminal width/height (GH7180). • Bug in OLS where running date when offset is negative (GH7195) • Bug in broadcasting with .div, integer dtypes and divide-by-zero (GH7325) • Bug in CustomBusinessDay.apply raiases NameError when np.datetime64 object is passed (GH7196)

(GH7542) • Bug in rolling_count() and expanding_*() functions unnecessarily producing error message for zero-length data (GH8056) • Bug in rolling_apply() and expanding_apply() interpreting min_periods=0 as clip long column data (GH8305) • Bug in DataFrame terminal display: Setting max_column/max_rows to zero did not trigger auto-resizing of dfs to fit terminal width/height (GH7180). • Bug in OLS where running date when offset is negative (GH7195) • Bug in broadcasting with .div, integer dtypes and divide-by-zero (GH7325) • Bug in CustomBusinessDay.apply raiases NameError when np.datetime64 object is passed (GH7196)

two more options to further customize the bar chart. Bar alignment is set with align='left'|'mid'|'zero', the default is “left”, which is backward compatible; You can now pass a list of color=[color_negative Changes • Timestamp.to_pydatetime will issue a UserWarning when warn=True, and the instance has a non- zero number of nanoseconds, previously this would print a message to stdout (GH14101). • Series.unique() in a reverse sorted DatetimeIndex (GH14316) • Bug in Series comparison operators when dealing with zero dim NumPy arrays (GH13006) • Bug in .combine_first may return incorrect dtype (GH7630, GH10567)

Changes • Timestamp.to_pydatetime will issue a UserWarning when warn=True, and the instance has a non- zero number of nanoseconds, previously this would print a message to stdout (GH14101). 1.1. v0.19.0 (October in a reverse sorted DatetimeIndex (GH14316) • Bug in Series comparison operators when dealing with zero dim NumPy arrays (GH13006) • Bug in .combine_first may return incorrect dtype (GH7630, GH10567) Bug in Series.resample using a frequency of Nano when the index is a DatetimeIndex and contains non-zero nanosecond parts (GH12037) • Bug in resampling with .nunique and a sparse index (GH12352) • Removed

Changes • Timestamp.to_pydatetime will issue a UserWarning when warn=True, and the instance has a non- zero number of nanoseconds, previously this would print a message to stdout (GH14101). • Series.unique() Python data analysis toolkit, Release 0.19.1 • Bug in Series comparison operators when dealing with zero dim NumPy arrays (GH13006) • Bug in .combine_first may return incorrect dtype (GH7630, GH10567) Bug in Series.resample using a frequency of Nano when the index is a DatetimeIndex and contains non-zero nanosecond parts (GH12037) • Bug in resampling with .nunique and a sparse index (GH12352) • Removed

two more options to further customize the bar chart. Bar alignment is set with align='left'|'mid'|'zero', the default is “left”, which is backward compatible; You can now pass a list of color=[color_negative Changes • Timestamp.to_pydatetime will issue a UserWarning when warn=True, and the instance has a non- zero number of nanoseconds, previously this would print a message to stdout (GH14101). • Series.unique() in a reverse sorted DatetimeIndex (GH14316) • Bug in Series comparison operators when dealing with zero dim NumPy arrays (GH13006) • Bug in .combine_first may return incorrect dtype (GH7630, GH10567)

over a datetimelike column (GH13393) • Bug in rolling.var where calculation is inaccurate with a zero-valued array (GH18430) 1.1.5.6 Reshaping • Error message in pd.merge_asof() for key datatype mismatch two more options to further customize the bar chart. Bar alignment is set with align='left'|'mid'|'zero', the default is “left”, which is backward compatible; You can now pass a list of color=[color_negative Changes • Timestamp.to_pydatetime will issue a UserWarning when warn=True, and the instance has a non- zero number of nanoseconds, previously this would print a message to stdout (GH14101). • Series.unique()

behavior, one can describe various statistical procedures, like standard- ization (rendering data zero mean and standard deviation 1), very concisely: In [86]: ts_stand = (df - df.mean()) / df.std() If the substring is found, the function returns its position. Keep in mind that Python indexes are zero-based and the function will return -1 if it fails to find the substring. In [28]: tips['sex'].str notation to extract a substring from a string by position locations. Keep in mind that Python indexes are zero-based. In [29]: tips['sex'].str[0:1].head() Out[29]: 67 F 92 F 111 F 145 F 135 F Name: sex,