R to Python

String methods vs stringr

1. Pandas allows you to slice all strings in a Series, but does not allow you to apply custom slices to each string (a la stringr::str_sub). This means there is no easy equivalent to using results from stringr::str_locate to subset strings.

2. While most Pandas string methods are under the .str accessor, the ones for ordering are not. To stringr::str_order() and stringr::str_sort(), use .argsort() and .sort_values().

3. stringr has an *_all() variant on several functions (e.g. str_replace, str_locate, str_extract, str_match). Pandas generally has equivalent behavior, but it is sometimes specified by using an alternative method (e.g. str.extractall()), and sometimes by using an argument (e.g. str_replace(..., n = 1)).

4. Pandas string methods are modeled after python str object methods AND stringr (This is mentioned in the .str accessor source code). However, it’s not always clear what accepts a regex (similar to stringr) and what does not (similr to str object methods).

   For example, .str.count() only accepts a regex. str.startswith() does not. Other methods like str.contains() accept a regex by default, but this can be disabled using the regex argument.

   This is not a big issue in practice, but warrants some caution / teaching strategy.