Add str.strip

[Uwe L. Korn]

• ✔️ pandas function
• ✔️ Python function
• ✔️ no need for a regular expression library
• ✔️ no need for a Unicode database
• ❌ cannot pre-compute output size

Pseudo-Code:

Inputs: to_strip

if to_strip is None:
    to_strip = list_of_whitespaces

builder = StringBuilder()
for row in rows:
    if isnull(row)
        builder.addnull()
    else:
        len = utf8_len(row)
        for i in range(len):
            if ut8_char(row, len - 1) in to_strip:
                len -= 1
            else:
                break
        builder.add(utf8_slice(row, 0, len))