Question

我有一个非常长的字符串，看起来与此相似。

355,356,357,358,359,360,361,382,363,364,365,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,368,369,313,370,371,372,373,374,375,376,377,378,379,380,381,382,382,382,382,382,382,383,384,385,380,381,382,382,382,382,382,386,387,388,389,380,381,382,382,382,382,382,382,390,391,380,381,382,382,382,382,382,392,393,394,395,396,397,398,399,....

当我尝试使用以下代码从字符串中删除数字382时。

String str = "355,356,357,358,359,360,361,382,363,364,365,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,368,369,313,370,371,372,373,374,375,376,377,378,379,380,381,382,382,382,382,382,382,383,384,385,380,381,382,382,382,382,382,386,387,388,389,380,381,382,382,382,382,382,382,390,391,380,381,382,382,382,382,382,392,393,394,395,396,397,398,399,...."
str = str.replace(",382,", ",");

但似乎并非所有事件都被替换。最初发生3000次以上的字符串在更换后仍留有约630次出现。

String.replace（）的功能是否有限？如果是这样，是否有可能实现我的需求？

Answer 1

我认为问题是你replace()的第一个参数，特别是382之后和之前的逗号（，）。如果你有＆＃34; 382,382,383＆＃34;，你只会匹配内部＆＃34;，382，＆＃34;并留下最初的一个。尝试：

str.replace("382,", "");

虽然这不符合＆＃34; 382＆＃34;在最后，因为它之后没有逗号。

完整的解决方案可能需要两个方法调用：

str = str.replace("382", "");  // Remove all instances of 382
str.replaceAll(",,+", ",");    // Compress all duplicates, triplicates, etc. of commas

这结合了两种方法：

str.replaceAll("382,?", "");  // Remove 382 and an optional comma after it.

注意：如果382在结尾，则后两种方法都会留下尾随逗号。

Answer 2

您还需要替换尾随的逗号（如果存在，如果列表中的最后一个则不存在）：

str = str.replaceAll("\\b382,?", "");

注意\b字边界以防止匹配"-,1382,-"。

以上将转换：

382,111,382,1382,222,382

为：

111,1382,222

Answer 3

试试这个

str = str.replaceAll(",382,", ",");

Answer 4

首先，删除匹配字符串中的前一个逗号。然后，使用java正则表达式将逗号替换为单个逗号，删除重复的逗号。

 String input = "355,356,357,358,359,360,361,382,363,364,365,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,360,361,363,366,368,369,313,370,371,372,373,374,375,376,377,378,379,380,381,382,382,382,382,382,382,383,384,385,380,381,382,382,382,382,382,386,387,388,389,380,381,382,382,382,382,382,382,390,391,380,381,382,382,382,382,382,392,393,394,395,396,397,398,399";
    String result = input.replace("382,", ","); // remove the preceding comma
    String result2 = result.replaceAll("[,]+", ","); // replace duplicate commas

    System.out.println(result2);

Answer 5

正如戴夫已经说过的，问题是你的模式重叠了。在字符串"...,382,382,..."中，有两次出现",382,"：

"...,382,382,..."
    -----         first occurrence
        -----     second occurrence

这两个匹配项在逗号处重叠，因此Java只能替换其中一个。在查找事件时，它还没有看到您替换模式的内容，因此当替换第一个匹配项时，它不会看到生成",382,"的新事件被替换为逗号。

如果您的数据已知不包含超过3位数的数字，那么您可以这样做：

str.replace("382,", "");

然后作为特例处理最后的事件。但是，如果您的数据可能包含大数字，则"...,1382,..."将替换为"...,1,..."，这可能不是您想要的。

以下是两个没有上述问题的解决方案：

首先，只需重复替换，直到不再发生任何变化：

String oldString = str;
str = str.replace(",382,", ",");
while (!str.equals(oldString)) {
    oldString = str;
    str = str.replace(",382,", ",");
}

之后，您将必须处理字符串末尾可能出现的事件。

其次，如果你有Java 8，你可以自己做更多的工作并使用Java流：

str = Arrays.stream(str.split(","))
    .filter(s -> !s.equals("382"))
    .collect(Collectors.joining(","));

首先将字符串拆分为＆＃34;，＆＃34;，然后过滤掉所有等于＆＃34; 382＆＃34;的字符串，然后再将其余字符串与＆＃34;连接，＆＃34;介于两者之间。

（两个代码段均未经过测试。）

String.replace（）不替换所有出现的

5 个答案: