Java 如何将字符串中的数字增加 1？
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How to increment the number in a String by 1?
提问by
I have a below String as -
我有一个下面的字符串 -
String current_version = "v2";
And here version can be either of these string as well - v3or v4or v10or v100or v500or v1000
并且这里的版本也可以是这些字符串中的任何一个 -v3或v4或v10或v100或v500或v1000
Now I am looking to increment the current_version from v2to v3. Meaning I always need to increment the current_version by 1.
现在我希望将 current_version 从v2增加到v3。这意味着我总是需要将 current_version 增加 1。
If current_version is v5, then I will increment it to v6.
如果 current_version 是v5，那么我会将它增加到v6。
How can I do this with a String?
我怎样才能用字符串做到这一点？
NOTE:-
笔记：-
I am getting current_versionstring value from some method which will always return me like this v2, v3, v4 only..
我current_version从某种方法中获取字符串值，它总是像这样返回我 v2、v3、v4。
采纳答案by Martin Dinov
If you want to parse the number after the v as an int and increment it by 1, just do so by substringing, adding 1 to the number and concatenating the resulting incremented number back into a string with "v" prepended:
如果要将 v 后面的数字解析为 int 并将其递增 1，只需通过子串化、将 1 添加到数字并将结果递增的数字连接回带有“v”前缀的字符串来执行此操作：
String version = "v1";
String newVersion = "v" + (Integer.parseInt(version.substring(1,version.length()))+1);
System.out.println(newVersion);
Alternatively, you could keep track of the current version in an int, increment that and construct your new Stringby appending that int to a "v", without having to call substring().
另外，你可以跟踪的当前版本在int，增量是构建新的String通过追加INT一个“V”，而不必调用substring()。
回答by Slimu
Why you don't store the version as an int and add the char 'v' when displaying the version? If you wish to do it with a String, you can make a substring of the initial one, parse it to int and after that add to'v' the result.
为什么不将版本存储为 int 并在显示版本时添加字符“v”？如果你想用一个字符串来做，你可以创建一个初始字符串的子字符串，将它解析为 int ，然后将结果添加到 'v' 。
currentVersion = "v" + (Integer.parseInt(currentVersion .substring(1)) + 1);
回答by exception1
try
尝试
int version = Integer.parseInt(current_version.replace("v", ""));
then you can increment it and add a get "v" + current_version
然后你可以增加它并添加一个 get "v" + current_version
回答by stinepike
I will suggest you to store the version in an int. so the codes will be following
我建议您将版本存储在 int 中。所以代码将遵循
int versionNumber = 1;
whenever you want to increment just increment it using
每当你想增加只是增加它使用
versionNumber++;
and to print or store as a complete version do following
并打印或存储为完整版本，请执行以下操作
String version = "v" + versionNumber;
回答by Zavior
If your format ever changes, this allows for a bit more flexibility:
如果您的格式发生变化，这将提供更大的灵活性：
String version = "v1234";
System.out.println("v" + (Integer.parseInt(version.replaceAll("[^0-9]", "")) + 1));
Use a regex to drop all non-digits, add one to the result.
使用正则表达式删除所有非数字，在结果中添加一个。
回答by ValerioMC
String oldVersion = "v100";
String[] splitString = oldVersion.split("v");
int newVersion = Integer.valueOf(splitString[1])+1;
String completeNewVersion = splitString[0] + newVersion;
System.out.print(completeNewVersion);
回答by B. Delbart
If you want another solution you can use this :
如果你想要另一个解决方案，你可以使用这个：
uint8_t versionNumber = 1;
char version[40];
sprintf(version,"v %d",versionNumber);
And you increment your variable "versionNumber" whenever you want !
您可以随时增加变量“versionNumber”！
