I have an input string and I want to use regex to check if this string has = and $, e.g:
Input:
name=alice$name=peter$name=angelina
Output: true
Input:
name=alicename=peter$name=angelina
Output: false
My regex does't work:
Pattern pattern = Pattern.compile("([a-z]*=[0-9]*$])*");
Matcher matcher = pattern.matcher("name=rob$name=bob");
With .matches(), you may use
Pattern pattern = Pattern.compile("\\p{Lower}+=\\p{Lower}+(?:\\$\\p{Lower}+=\\p{Lower}+)*"); // With `matches()` to ensure whole string match
Details
\p{Lower}+ - 1+ lowercase letters (use \p{L} to match any and \p{Alpha} to only match ASCII letters)= - a = char\p{Lower}+ - 1+ lowercase letters(?:\\$\\p{Lower}+=\\p{Lower}+)* - 0 or more occurrences of:
\$ - a $ char\p{Lower}+=\p{Lower}+ - 1+ lowercase letters, = and 1+ lowercase letters.See the Java demo:
List<String> strs = Arrays.asList("name=alice$name=peter$name=angelina", "name=alicename=peter$name=angelina");
Pattern pattern = Pattern.compile("\\p{Lower}+=\\p{Lower}+(?:\\$\\p{Lower}+=\\p{Lower}+)*");
for (String str : strs)
System.out.println("\"" + str + "\" => " + pattern.matcher(str).matches());
Output:
"name=alice$name=peter$name=angelina" => true
"name=alicename=peter$name=angelina" => false
* quantifiers, ideone.com/p5mgo2You have extra ] and need to escape $ to use it as a character though you also need to match the last parameter without $ so use
([a-z]*=[a-z0-9]*(\$|$))*
• [a-z]*= : match a-z zero or more times, match = character
• [a-z0-9]*(\$|$): match a-z and 0-9, zero or more times, followed by either $ character or end of match.
• ([a-z]*=[a-z0-9]*(\$|$))*: match zero or more occurences of pairs.
Note: use + (one or more matches) instead of * for strict matching as:
([a-z]+=[a-z0-9]+(\$|$))*
$and check