float to string

就是用 str( ) 就可以

fnumber = 1.23
fstring = str(fnumber)

fstring 就會是 '1.23'

substring

沒有 substring，因為和 C 一樣，直接用 [from:to] 取出

data = 'this is a test'
sub = data[3:10]

sub 會是 's is a '