REXX -从CSV文件解析

Question

我在从文本文件中解析CSV时遇到了问题，不知道你们是否可以帮助我。到目前为止，我有以下几点：

CSV文件(DATA.txt)看起来像这样，它总是有15个字段，全部用逗号分隔。并非所有字段都是必填字段，因此一些字段将被填写，而另一些字段则为空。

Seattle,Lastname,Firstname,DOB,SEX,etc,etc
Seattle,Lastname,Firstname,DOB,,etc,etc
Portland,Lastname,Firstname,DOB,SEX,,,etc
Portland,Lastname,Firstname,DOB,SEX,etc,etc

这是我的REXX代码

SOURCEFILE = "C:\DATA\DATA.TXT"
IF A=2 THEN DO COUNTER=1 TO LINES(SOURCEFILE)
    PARSE VALUE LINEIN(SOURCEFILE) WITH CITY "," LAST_NAME "," FIRST_NAME "," MOM_NAME "," MIDDLE_NAME "," DAD_NAME "," DOB "," etc "," etc "," etc "," etc "," SEX "," etc "," etc
    CALL SETCURSOR 4,23
    CALL CREATEDATA
END

CREATEDATA:
CALL TYPE CITY
CALL PRESS TAB
CALL TYPE LAST_NAME
CALL PRESS TAB
CALL TYPE DATE(U)
CALL PRESS TAB
CALL TYPE FIRST_NAME
CALL PRESS TAB
CALL PRESS ENTER
RETURN

我不确定我应该在解析时使用ARG还是VAR，或者我是否正确地写了前两行。我知道我的CREATEDATA函数工作正常，因为我得到的是输入的“城市”，而不是解析后的值。任何帮助都将不胜感激。谢谢!

Answer 1

下面是一些评论：

1) Windows系统上的Lines(SourceFile)可能涉及读取整个文件来计算CR-LF序列。然后，您的Parse value LineIn(SourceFile)循环再次读取它。典型的Rexx方法是：

Address SYSTEM 'TYPE' SourceFile with output stem Lines.
Do Counter = 1 to Lines.0
    Parse var Lines.Counter ...
End
Drop Lines.

至少，只要文件不是太大以至于在数组中保存它会占用大量内存。

2)你在循环的末尾进入了CreateData，这就是为什么你会看到“城市”。在该End指令后面需要一个Return或Exit。

3)根据#2，很明显Parse永远不会被执行，因为City是未初始化的( Rexx中未初始化变量的值是它的大写名称)。它是以A=2为条件的，不能是这样的。

Answer 2

一个问题是if A=2 then in的用途是什么？

IF A=2 THEN DO COUNTER=1 TO LINES(SOURCEFILE)

如果A != 2，则绕过循环。我怀疑你的程序应该是：

SOURCEFILE = "C:\DATA\DATA.TXT"
DO COUNTER=1 TO LINES(SOURCEFILE) 
    PARSE VALUE LINEIN(SOURCEFILE) WITH CITY "," LAST_NAME "," FIRST_NAME "," MOM_NAME "," MIDDLE_NAME "," DAD_NAME "," DOB "," etc "," etc "," etc "," etc "," SEX "," etc "," etc
    CALL SETCURSOR 4,23
    CALL CREATEDATA
END

RETURN   /* prevent the fall through to createdata */

CREATEDATA:




---------------------------

parse语句具有以下基本格式

解析源

其中源冰块

arg -过程调用的参数-从堆栈中拉出的数据var - data来自变量值...使用内联提供的数据

因此您的解析可以像这样完成

   linein = LINEIN(SOURCEFILE)
   PARSE var linein CITY "," LAST_NAME "," FIRST_NAME "," MOM_NAME "," MIDDLE_NAME "," DAD_NAME "," DOB "," etc "," etc "," etc "," etc "," SEX "," etc "," etc

或

    DO COUNTER=1 TO LINES(SOURCEFILE) 
        CALL SETCURSOR 4,23
        CALL CREATEDATA LINEIN(SOURCEFILE)
    END

    RETURN   /* prevent the fall through to createdata */

    CREATEDATA:
    parse arg CITY "," LAST_NAME "," FIRST_NAME "," MOM_NAME "," MIDDLE_NAME "," DAD_NAME "," DOB "," etc "," etc "," etc "," etc "," SEX "," etc "," etc

最后，罗斯说，你应该尽量避免行(源文件)，因为它涉及到读取整个文件