. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427 21.8 Thread-safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427 gets python 2 and python 3 compatible string methods (__str__, __bytes__, and __repr__). Plus string safety throughout. Now employed in many places throughout the pandas library. (GH4090, GH4092) 1.1.2 I/O non-unique indexing in series via .ix/.loc and __getitem__ (GH4246) – Fixed non-unique indexing memory allocation issue with .ix/.loc (GH4280) • DataFrame.from_records did not accept empty recarrays

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558 23.9 Thread-safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558 option io.hdf.dropna_table (GH4625) • pass thru store creation arguments; can be used to support in-memory stores 1.2.7 DataFrame repr Changes The HTML and plain text representations of DataFrame now show gets python 2 and python 3 compatible string methods (__str__, __bytes__, and __repr__). Plus string safety throughout. Now employed in many places throughout the pandas library. (GH4090, GH4092) 1.3.2 I/O

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618 23.9 Thread-safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618 database URI. You only need to create the engine once per database you are connecting to. For an in-memory sqlite database: 12 Chapter 1. What’s New pandas: powerful Python data analysis toolkit, Release sqlalchemy import create_engine # Create your connection. In [44]: engine = create_engine(’sqlite:///:memory:’) This engine can then be used to write or read data to/from this database: In [45]: df = pd.DataFrame({’A’:

. . . . . . . . . . . . . . . . . . . 172 3 Frequently Asked Questions (FAQ) 175 3.1 DataFrame memory usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 3.2 PeriodIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 768 27.9 Thread-safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 768 values for columns that contain NA values and have dtype object (GH8778). 1.1.3 Performance • Reduce memory usage when skiprows is an integer in read_csv (GH8681) • Performance boost for to_datetime conversions

. . . . . . . . . . . . . . . . . . . 166 3 Frequently Asked Questions (FAQ) 169 3.1 DataFrame memory usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 3.2 PeriodIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 754 27.9 Thread-safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 754 dtype that utilizes memory based on the level size. In prior versions, the memory usage was a constant 8 bytes per element in each level. In addition, in prior versions, the reported memory usage was incorrect

. . . . . . . . . . . . . . . . . 238 i 4 Frequently Asked Questions (FAQ) 241 4.1 DataFrame memory usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 4.2 Byte-Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 890 28.9 Thread-safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 890 presence of the HTTP Content-Encoding header in the response (GH8685) • Enable writing Excel files in memory using StringIO/BytesIO (GH7074) • Enable serialization of lists and dicts to strings in ExcelWriter

TimedeltaIndex/Scalar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 .dt . . . . . . . . . . . . . . . . . . . 341 4 Frequently Asked Questions (FAQ) 343 4.1 DataFrame memory usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343 4.2 Byte-Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 819 22.11.1 Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 819 22.11

TimedeltaIndex/Scalar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 .dt . . . . . . . . . . . . . . . . . . . 343 4 Frequently Asked Questions (FAQ) 345 4.1 DataFrame memory usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345 4.2 Byte-Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 821 22.11.1 Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 821 22.11

8 Pandas Google BigQuery support has moved . . . . . . . . . . . . . . . . . . . . . 27 1.3.2.9 Memory Usage for Index is more Accurate . . . . . . . . . . . . . . . . . . . . . . 27 1.3.2.10 DataFrame TimedeltaIndex/Scalar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 1.16.1.3 Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 1.16.1.4 .dt accessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908 21.11.1 Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908 21.11

8 Pandas Google BigQuery support has moved . . . . . . . . . . . . . . . . . . . . . 26 1.2.2.9 Memory Usage for Index is more Accurate . . . . . . . . . . . . . . . . . . . . . . 26 i 1.2.2.10 DataFrame TimedeltaIndex/Scalar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 1.15.1.3 Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 1.15.1.4 .dt accessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904 21.11.1 Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904 21.11