如何在Java中删除字符串开头而不是制表符的空格？

Question

I, have to remove leading whitespace from a string except the \\t character. For example

" \\thello"

should become

"\\thello"

I've tried with

stringToTrim = stringToTrim.replaceAll("^\\s+", "");

but the regex match also with tab character and the result is

"hello"

Is it possible to remove leading whitespaces but not tabs with regex?

Answer 1

In Java, you may use a character class subtraction to restrict a more generic pattern.

Use

stringToTrim = stringToTrim.replaceFirst("^[\\s&&[^\t]]+", "");

Here,

• ^ - matches the start of string
• [ - start of a character class
• \\\\s - any whitespace pattern
• && - intersection operator
• [^\\t] - any char but a tab
• ] - end of the character class
• + - a quantifier matching one or more occurrences.

Note since there will only be 1 replacement, it makes sense to use .replaceFirst rather than .replaceAll .

Answer 2

如果您只对空白感兴趣，那么stringToTrim.replaceFirst("^ *", "")将为您服务。