请教正则表达式问题， 达人请进！

[scbb]

CSV解析， 以前自己写得不是用正则的。

CSV是,号分隔一个个字符串项， 以\r\n或者\r换行。

如果单个字符项里本身含有,号或者\r\n的， 那么这项就需要用" "弄起来。

比如abc,"a,b",c
就是
abc
a,b
c

而且如果没有,\r\n这些特殊字符得项也可以用""，
但是""不记入真正的字符。
例abc,"bbb",c
就是
abc
bbb
c

请问这样的分隔， 正则表达式怎么写？
谢谢！

[lsy110]

試試這個，初步測試沒問題：

<SCRIPT LANGUAGE="JavaScript">
<!--
var sourceString="abc,\"a,b\",abdd,\"this,this,this\",c";

// mach "xxx"
var reg1=/^\"[^\"]+\"/;

// mach xxx
var reg2=/^\w+,/;

document.writeln("Source String:" + sourceString + " <br>" );
document.writeln("<hr>");
document.writeln("<table border='1'>");
document.writeln("<tr><td>Mached</td><td>Remain</td></tr>");

while (true)
{

if (sourceString.length == 0)
break;

var result1=reg1.exec(sourceString);// match
var result2=reg2.exec(sourceString);

document.writeln("<tr>");

if(result1 != null) // find the "xxxx",
{
// delete the ""
var strTemp=result1[0].substring(1,result1[0].length-1);
document.writeln("<td>" + strTemp + " </td>" );
sourceString=sourceString.substring(result1.index+result1[0].length+1);
document.writeln("<td>" + sourceString + "</td>");
}
else if (result2 != null) // find the xxx,
{
// delete the "," char
var strTemp=result2[0].substring(0,result2[0].length-1);

document.writeln("<td>" + strTemp + " </td>" );
sourceString=sourceString.substring(result2.index+result2[0].length);
document.writeln("<td>" + sourceString + "</td>");
}
else // find nothing or the last one.
{
document.writeln("<td>" + sourceString + " </td>" );
document.writeln("<td> NA </td>");

sourceString="";
}
document.writeln("</tr>");
}

document.writeln("</table>");
//-->
</SCRIPT>

有什么問題再測！呵呵...

[lsy110]

對了，如果有換行的情況就要加上：/xxx/m來多行匹配了

[ashes]

import java.util.regex.*;
import java.util.*;

public class CSVParser {

public static ArrayList parse(String str1) {
ArrayList list = new ArrayList();
Pattern p = Pattern.compile("\"([^\"]+)\"|([^,]+)");
Matcher m = p.matcher(str1);
while(m.find()) {
list.add(m.group().replaceAll("\"", ""));
}
return list;
}

public static void main(String[] args) throws Throwable {
String csv1 = "a,bc,\"a,b\",bc,c";
String csv2 = "abc,\"abc\",c";
ArrayList list1 = CSVParser.parse(csv1);
System.out.println("list1");
for (int i =0; i < list1.size(); i++)
System.out.println(list1.get(i));
ArrayList list2 = CSVParser.parse(csv2);
System.out.println("list2");
for (int i =0; i < list2.size(); i++)
System.out.println(list2.get(i));
}
}

[scbb]

上面的完全正确， 能不能帮我解析行的也一起做了？

因为,,中间有\r\n的情况因为和那个做法一样的。

行吗？

好了马上给分。

[scbb]

st.add(m.group().replaceAll("\"", ""));
这样是不是把不是开头的"也去掉了。

PS刚才没有说"也是个特殊字符。
要是"是内容的一部分也应该要
ac,"aaaba"aaa",ab

真正内容是
ac
aaaba"aaa
ab

楼上的不会觉得我太过分吧？
真的都做出来了， 我还可以再加分

[scbb]

ashes(灰尘) ( ) 大侠在不在啊？

[scbb]

最好能给出完整代码， 谢谢。
150分给第一个解决的。

[scbb]

没有人gz吗？
还是觉得分不够？

[fpwang]

不知有没有帮助
文法={Vt, Vn, S, p}
Vt={字母，','，'\r\n'，'\r'}
Vn={CVS，字符串，字符串1，字符串2，字母}
S=CVS

p:
CVS -> 字符串(,字符串)*
字符串 -> 字符串1 | "字符串1" | "字符串2"
字符串1 -> 字母+
字符串2 -> 字母+,字母+ | 字母+\r字母+ | 字母+\r\n字母+
字母 -> a|b|c|………… |z

[star821116]

你试试下面的例子,是Javacookbook上面的,唉,我早就说好好好看看RE,这段时间忙过了要好好看看了^_^

import java.io.*;
import org.apache.regexp.*;

/* Simple demo of CSV matching using Regular Expressions.
* Does NOT use the "CSV" class defined in the Java CookBook.
* RE Pattern from Chapter 7, Mastering Regular Expressions (p. 205, first edn.)
*/
public class CSVRE {
/** The rather involved pattern used to match CSV's consists of three
* alternations: the first matches quoted fields, the second unquoted,
* the third null fields
*/
public static final String CSV_PATTERN =
"\"([^\"\\\\]*(\\\\.[^\"\\\\]*)*)\",?|([^,]+),?|,";

public static void main(String[] argv) throws IOException, RESyntaxException
{
String line;

// Construct a new Regular Expression parser.
Debug.println("regexp", "PATTERN = " + CSV_PATTERN); // debug
RE csv = new RE(CSV_PATTERN);

BufferedReader is = new BufferedReader(new InputStreamReader(System.in));

// For each line...
while ((line = is.readLine()) != null) {
System.out.println("line = `" + line + "'");

// For each field
for (int fieldNum = 0, offset = 0; csv.match(line, offset); fieldNum++) {

// Print the field (0=null, 1=quoted, 3=unquoted).
int n = csv.getParenCount()-1;
if (n==0) // null field
System.out.println("field[" + fieldNum + "] = `'");
else
System.out.println("field[" + fieldNum + "] = `" + csv.getParen(n) + "'");

// Skip what already matched.
offset += csv.getParen(0).length();
}
}
}
}
class Debug {
/** Static method to see if a given category of debugging is enabled.
* Enable by setting e.g., -Ddebug.fileio to debug file I/O operations.
* Use like this:<BR>
* if (Debug.isEnabled("fileio"))<BR>
* System.out.println("Starting to read file " + fileName);
*/
public static boolean isEnabled(String category) {
return System.getProperty("debug." + category) != null;
}

/** Static method to println a given message if the
* given category is enabled for debugging.
*/
public static void println(String category, String msg) {
if (isEnabled(category))
System.out.println(msg);
}
/** Same thing but for non-String objects (think of the other
* form as an optimization of this).
*/
public static void println(String category, Object stuff) {
println(category, stuff.toString());
}
}

[scbb]

to star821116(冰冻三尺非一日之寒)
我看了一下， 那使用的是is.readLine()，
这样如果,,中间本身有\r\n，但是这个并不表示下一行的，所以读csv的行就不对了。

而且它使用的是
import org.apache.regexp.*;
这个包， 不是1.4自带的， 你能不能帮我移植过去？
我这里没有org.apache.regexp的文档

看别人德正则表达式满难懂的。
我这样试过
public static final String CSV_PATTERN =
"\"([^\"\\\\]*(\\\\.[^\"\\\\]*)*)\",?|([^,]+),?|,";
java.util.regex.Pattern p = java.util.regex.Pattern.compile(CSV_PATTERN);
Matcher matcher = p.matcher("abc,\"a,bbc\",ad");
System.out.println(matcher.matches());

出来的是false，应该怎么写呢？？

说实话那个表达式我看不懂:(

[whyxx]

一群高手啊,正在学习正则表达式,进来学习学习

[kiddycoffee]

偶来帮你一下吧：

import java.util.regex.*;

public class RETest {
public static void main(String[] args) {
String targetStr = "aaa,\"b b\",\"c,c\"";
String regStr = "([\\p{Alnum}]+)" +
"|(\"[\\p{Alnum}\\p{Space},]+)\"";
Pattern patt = Pattern.compile(regStr);
Matcher m = patt.matcher(targetStr);
int count = 0;

while (m.find()) {
String str = m.group();
if (str.charAt(0) == '\"') {
str = str.substring(1, str.length()-1);
}
count++;
System.out.println("Matche #" + count + ": " + str);
}

System.out.println("Total " + m.groupCount() + " result(s) found!\n");
}
}

[kiddycoffee]

啊，有个地方错了，最后一行 m.groupCount() 应为 count 才对。

[ashes]

这几天一直忙着做asp,access(郁闷啊)
改了一下，效果不是很好

import java.util.regex.*;
import java.util.*;
import java.io.*;

public class CSVParser {

private StringBuffer buf = null;

public ArrayList parse() {
String str;
ArrayList list = new ArrayList();
Pattern p = Pattern.compile("(\"(.*)\")|(([^,\\x0d]+))");
//Pattern p = Pattern.compile("([^\\x0d]+)");
Matcher m = p.matcher(buf);

while(m.find()) {
str = m.group();
//System.out.println(str);
//str = str.replaceAll("(?sm)(\"(\"))|(\"([^\"])?)|(^\\x0a(.*))", "$2");
str = str.replaceAll("(?sm)(^\\x0a(.*))", "$2");
str = str.replaceAll("(?sm)(^\"(.*)\"$)", "$2");
str = str.replaceAll("(?sm)(\"(\"))", "$2");
//System.out.println(str);
list.add(str);
}
return list;
}

public void readCSVFile(File CSVFile) {
int chr;
buf = new StringBuffer("");
try {
BufferedReader in = new BufferedReader(new FileReader(CSVFile));
while((chr=in.read()) != -1) {
buf.append((char)chr);
//System.out.print((char)chr);
}
in.close();
System.out.println("-------------csv file content--------------");
System.out.print(buf);
} catch (FileNotFoundException fnfex) {
fnfex.printStackTrace();
} catch (IOException ioex) {
ioex.printStackTrace();
}
}

public static void main(String[] args) throws Throwable {
File file = new File("Book1.csv");
CSVParser parser = new CSVParser();
parser.readCSVFile(file);
ArrayList list = parser.parse();
int size = list.size();
System.out.println("\n\n--------------parsed result------------------");
System.out.println("size = " + size);
for (int i = 0; i < size; i++) {
System.out.println("list[" + i + "] = " + list.get(i));
}
}
}


用notepad打开的Book1.csv内容
a,bc,"a,b",bc,c
a,ab c,c,,
a,"aaaba""aaa",ab,,
a,"a
b
c","a b ,c",d,





运行结果
-------------csv file content--------------
a,bc,"a,b",bc,c
a,ab c,c,,
a,"aaaba""aaa",ab,,
a,"a
b
c","a b ,c",d,
--------------parsed result------------------
size = 16
list[0] = a
list[1] = bc
list[2] = a,b
list[3] = bc
list[4] = c
list[5] = a
list[6] = ab c
list[7] = c
list[8] = a
list[9] = aaaba"aaa
list[10] = ab
list[11] = a
list[12] = a
b
c
list[13] = a b ,c
list[14] = d
list[15] =


让我郁闷的是不知道为什么要多次replaceAll,此处效率低