Java regex for specific case -

i trying reformat string desired format. have been trying figure out while can't think of elegant solution using regexs. have come solution using string's indexof() , replace() it's not pretty.

i want convert string there 1 space on each side of "-".

possible inputs:

"abc- abc" "abc -abc" "abc - abc" "abc-abc"  

and each case should converted to

"abc - abc" 

thanks help. let me know if need more clarification.

using string#replaceall:

string pattern = "\\s*-\\s*"; string s1 = "abc- abc"; string s2 = "abc -abc"; string s3 = "abc - abc"; string s4 = "abc-abc"; system.out.println(s1.replaceall(pattern, " - ")); system.out.println(s2.replaceall(pattern, " - ")); system.out.println(s3.replaceall(pattern, " - ")); system.out.println(s4.replaceall(pattern, " - ")); 

explanation of "\\s*-\\s*" regex:

• \\s => space (in fact, \s java needs double \\)
• * => 0 or more
• - => simple '-'

more info regular expressions: regular expression basic syntax reference