how to judge some bytes is or not a-z,A-Z?

i read some files using fread ,then some bytes display like blank , but there is sth.,i want to delete these special chars ,how to make it ? thanks

Answer 1

[Mischa Kim]

Roger, use regular expressions, something like

 str = 'a b{}c1230O /&" â'
 str =
 a b{}c1230O /&" â
 str_rep = regexprep(str,'[^a-zA-Z0-9]','')
 str_rep =
 abc1230O