Re: Reading, Modifying, and Writing a file with data with quotation marks
- To: mathgroup at smc.vnet.net
- Subject: [mg29419] Re: Reading, Modifying, and Writing a file with data with quotation marks
- From: Tom Burton <tburton at cts.com>
- Date: Tue, 19 Jun 2001 05:35:37 -0400 (EDT)
- References: <9gkb6n$dul$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hello,
On Mon, 18 Jun 2001 07:39:03 +0000 (UTC), in comp.soft-sys.math.mathematica you wrote:
>I would like to modify a data file on disk which has
>the data enclosed in quotation marks.
>A much-shortened example would be as follows...
Given the following file,
In[374]:=
!!d:\local\mmatest\test2.txt
"big","left","15","0","0","21.87","0","0","","0","smy"
"82","back","up","24","0","0","0","50","0","0","0","0","984"
"44","","up","symm"
reading it is relatively easy, provided that the character "," does not appear in any string. Read the file as string-valued words, creating a separate list for each line:
In[367]:=
data = ReadList["d:\\local\\mmatest\\test.txt", Word,
WordSeparators->{","}, RecordLists->True];
Modify the data:
In[368]:=
data2 = Insert[data,"\"0\"",{{1,4},{1,4},{2,5},{2,5},{2,5}}];
This next part is a bit messy. Perhaps someone will suggest a better way. Combine each line of strings into one string, inserting comma-strings between each word and appending a new-line character:
In[369]:=
data3 = StringDrop[StringJoin@@(# /. s_String:>StringJoin[s,","]), -1] <> "\n" & /@ data2;
This form of the data is just right for WriteString:
In[370]:=
stream=OpenWrite["d:\\local\\mmatest\\test2.txt"];
WriteString[stream,Sequence@@data3]
Close[stream];
Then
In[373]:=
!!d:\local\mmatest\test2.txt
"big","left","15","0","0","21.87","0","0","","0","smy"
"82","back","up","24","0","0","0","50","0","0","0","0","984"
"44","","up","symm"
If the separator "," appears some of the words, then you must work a bit harder. I have a function that can do that job. Let me know if you need it.
Regards,
Tom Burton