mb_convert_kana

This is a function to convert one-byte into two-byte or two-byte into one byte.

option	meaning
r	alphabet two-byte to one-byte
R	alphabet one-byte to two-byte
n	number two-byte to one-byte
N	number one-byte to two-byte
a	alphabet and number two-byte to one-byte
A	alphabet and number one-byte to two-byte
s	space two-byte to one-byte
S	space one-byte to two-byte
k	katakana two-byte to one-byte
K	katakana one-byte to two-byte
h	hiragana two-byte to one-byte
H	hiragana one-byte to two-byte
c	two-byte katakana to two-byte hiragana
C	two-byte hiragana to two-byte katakana
V	Collapse voiced sound mark and convert them into a character. Use with "K","H"