Pandas

Starting with v3, pandas will use Copy-On-Write, which is a step towards sane data management (see here for context). We recommend, and are using in course code, setting

pd.options.mode.copy_on_write = True

Note: confusing aspects of memory management remain. For instance, previously

df.x[0] = 123

set the first element of column x to 123 and produced a SettingWithCopyWarning. Now, this operation silently does nothing. But, this is in development, so perhaps it will change?