Reputation: 970

How to split a string with double quotes " as the delimiter?

I tried splitting like this-

tableData.split("\\"")

but it does not work.

Upvotes: 2

Answers (7)

valentine

Reputation: 457

You can actually split without the backward slash. You only have to use single quote

tableData.split('"');

Upvotes: 0

Zhedar

Reputation: 3510

You have escaped the \ by putting in \ twice, try

tableData.split("\"")

Why does this happen?
A backslash escapes the following character. Since the next character is another backslash, the second backslash will be escaped, thus the doublequote won't.
Your resulting escaped string is \", where it should really be just ".

Edit:
Also keep in mind, that String.split() interprets its pattern parameter as a regular expression, which has several special characters, which have to be escaped in the resulting string.
So if you want split by a .(which is a special regex character), you need to specify it as String.split("\\."). The first backslash escapes the escaping function of the second backlash and would result in "\.".

In case of regex characters you could also just use Pattern.quote(); to escape your desired delimiter, but this is far out of the scope the question orignally had.

Upvotes: 4

Pshemo

Reputation: 124215

It seems that you tried to escape it same way as you would escape | which is "\\|". But difference between | and " is that

| is metacharacter in regex engine (it represents OR operator)
" is metacharacter in Java language in string literal (it represents start/end of the string)

To escape any String metacharacter (like ") you need to place before it other String metacharacter responsible for escaping which is \¹. So to create String which would contain " like this is "quote" you would need to write it as

String s = "this is \"quote\"";
//                  ^^     ^^ these represent " literal, not end of string

Same idea is applied if we would like to create \ literal (we would need to escape it by placing another \ before it). For instance if we would want to create string representing c:\foo\bar we would need to write it as

String s = "c:\\foo\\bar";
//            ^^    ^^    these will represent \ literal

So as you see \ is used to escape metacharacters (make them simple literals).
This character is used in Java language for Strings, but it also is used in regex engine to escape its metacharacters:
\, ^, $, ., |, ?, *, +, (, ), [, {.

If you would like to create regex which will match [ character you will need to use regex \[ but String representing this regex in Java needs to be written as

String leftBracketRegex = "\\[";
//                         ^^ - Remember what was said earlier? 
//                              To create \ literal in String we need to escape it

So to split on [ we would need to invoke split("\\[") because regex representing [ is \[ which needs to be written as "\\[" in Java.

Since " is not special character in regex but it is special in String we need to escape it only in string literal by writing it as

split("\"");

1) \ is also used to create other characters line separators \n, tab \t. It can also be used to create Unicode characters like \uXXXX where XXXX is index of character in Unicode table in hexadecimal form.

Upvotes: 7