英文:
How do I print a back slash?
问题
当我尝试使用System.out.println("\\\\");时，它会打印出两个反斜杠，我只想打印一个。
英文:
When I try System.out.println("\\\\");, it prints two back slashes, I only want to print one.
答案1
得分: 4
System.out.println("\\\"");. 反斜杠是‘转义’字符：您写一个反斜杠，然后再写一个其他字符，两者共同表示一个单个字符（字符串长度为1）；这是一种通常难以正常书写的字符。
"\n" 长度为1，是换行字符。
"\\\"" 长度为1，是一个单独的反斜杠。
英文:
System.out.println("\\");. Backslash is the 'escape' character: you write one backslash, and then one other character which together represents a single character (the string length would be 1); a character that is hard to write normally.
"\n" has length 1 and is a newline character.
"\\" has length 1 and is one single backslash.
答案2
得分: 2
只是为了完整地呈现情景。在Java正则表达式/Pattern中，当您想匹配文字反斜杠时，使用"\\\\"。您需要为正则表达式转义一次，然后两个反斜杠都需要再次转义...因为它是一个字符串文字。
简而言之：
"\\"用于字符串文字中的文字反斜杠"\\\\"用于在字符串文字中表示的正则表达式中匹配文字反斜杠
（如果您仔细考虑，这一切都是有道理的。）
英文:
Just to complete the picture. You use "\\\\" when you want to match a literal backslash in a Java regex / Pattern. You need to escape once for the regex, and then both backslashes need to be escaped again ... because it is a String literal.
In short:
"\\"for a literal backslash in a string literal"\\\\"to match a literal backslash in a regex expressed as a string literal
(It all makes sense if you think about it carefully.)
答案3
得分: 0
只需执行：
\\
示例可在此处查看：
System.out.println("\\");
生成：
\
英文:
Just do:
\\
Example can be seen here:
System.out.println("\\");
Which produces:
\
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