正则表达式在java中检查带下划线的字符串名称
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Regex expression to check for string name with underscore in java
提问by MindBrain
I am new to regex expressions in java. How do I check if the file name has the following format update_9_0_27?
Is it something like [0-9][\\_][0-9][\\_][0-100]?
我是 Java 中正则表达式的新手。如何检查文件名是否具有以下格式update_9_0_27？它是这样的[0-9][\\_][0-9][\\_][0-100]吗？
采纳答案by Andrew Clark
The following should work:
以下应该工作：
^[a-zA-Z]+_\d_\d_\d{1,2}$
The ^and $are beginning of string anchors so that you won't match only part of a string. Each \dwill match a single digit, and the {1,2}after the final \dmeans "match between one and two digits (inclusive)".
在^和$开始串锚，这样你就不会只匹配字符串的一部分。每个\d将匹配一个数字，{1,2}最后的后面\d表示“匹配一位和两位数字（包括）”。
If the updateportion of the file name is always constant, then you should use the following:
如果update文件名的部分始终不变，则应使用以下内容：
^update_\d_\d_\d{1,2}$
Note that when creating this regex in a Java string you will need to escape each backslash, so the string will look something like "^update_\\d_\\d_\\d{1,2}$".
请注意，在 Java 字符串中创建此正则表达式时，您需要对每个反斜杠进行转义，因此该字符串将类似于"^update_\\d_\\d_\\d{1,2}$".
回答by RichardTheKiwi
Are the digit positions fixed, i.e. 1-1-2?
数字位置是否固定，即 1-1-2？
^update\_\d\_\d\_\d\d$
Used in a Java string, you'd need to escape the backslashes
在 Java 字符串中使用，您需要转义反斜杠
"^update\_\d\_\d\_\d\d$"
If by [0-9][\\_][0-9][\\_][0-100]you mean single-digit, underscore, single-digit, underscore, zero-to-one-hundred, and this sequence can appear anywhere in the string, then
如果[0-9][\\_][0-9][\\_][0-100]您的意思是单个数字、下划线、单个数字、下划线、零到一百，并且此序列可以出现在字符串中的任何位置，那么
".*[0-9][_][0-9][_](100|[1-9][0-9]|[0-9]).*"
Notice that I have now used [_]as an alternative to \_for specifying a literal underscore. The last part tests for 0-100 specifically.
请注意，我现在已用作指定文字下划线[_]的替代方法\_。最后一部分专门测试 0-100。
