只替換字符串中的某些字符

Question

我正在尋找一種Java方式來替換沒有循環的序列中的匹配字符。

例

String x = "" 
    String pattern = "12" 
    String ex1 = "1254" 
    x = ex1.replace(pattern, ""); 
    System.out.print(x) 
    Output: 
    54 
    In this case 1254 a match is found: 12 

然而，

String x = "" 
    String pattern = "12" 
    String ex1 = "154" 
    x = ex1.replace(pattern, ""); 
    System.out.print(x) 
    Output: 
    154 
    In this case no replacement takes place. 
    The desired output in this case would be: 

    54 

    because only 1 is found from the pattern 

這是因爲圖案應在字完全匹配。然而，是否有一個函數只能從模式中匹配的字符被替換？

Answer 1

如何使用character class

x = ex1.replaceAll("[12]", "");