Editing Text Files - Easiest Way To Merge Every Other Line

  • Thread starter Sam032789
  • Start date
  • Tags
    File Text
They come from the days of manual typewriters and were carried over to computers. Windows adopted the CR+LF combination while Unix and derivatives (Linux, Mac OS X, etc.) use LF.
  • #1
Sam032789
11
0
Hello! I have a file that looks like this:

T,2009,05,06,15,54,34
D,NBXX,500,1.032e-4,7.657e-5,4.956e-5,9.404e-6,7.269e-6,6.667e-6
T,2009,05,06,15,55,34
D,NBXX,440,1.032e-4,7.665e-5,4.911e-5,9.303e-6,7.292e-6,6.507e-6
T,2009,05,06,15,56,34
D,NBXX,380,1.041e-4,7.743e-5,5.073e-5,9.635e-6,7.639e-6,6.867e-6
T,2009,05,06,15,57,34
D,NBXX,320,1.027e-4,7.628e-5,4.938e-5,9.491e-6,7.596e-6,6.489e-6
T,2009,05,06,15,58,34
D,NBXX,260,1.014e-4,7.490e-5,4.852e-5,9.352e-6,7.325e-6,6.657e-6
T,2009,05,06,15,59,34
D,NBXX,200,1.010e-4,7.408e-5,4.763e-5,9.408e-6,7.383e-6,6.794e-6
.
.
.
(etc.)

Where every line beginning with a T is a new data set. So basically I need each line in the file to look like this:

T,2009,05,06,15,59,34 D,NBXX,200,1.010e-4,7.408e-5,4.763e-5,9.408e-6,7.383e-6,6.794e-6

I need to merge every other line so that each data set lies on the same line. There can just be a space in between the two data points, a comma is not necessary.

So what's the easiest way to go about doing this? I was thinking something along the lines of sed, awk, or grep. Help is greatly appreciated.
 
Technology news on Phys.org
  • #2
Code: 
sed -e '{N; s/\n/ / }' FILENAME > OUTPUTFILENAME
produces a file containing
Code: 
T,2009,05,06,15,54,34 D,NBXX,500,1.032e-4,7.657e-5,4.956e-5,9.404e-6,7.269e-6,6.667e-6
T,2009,05,06,15,55,34 D,NBXX,440,1.032e-4,7.665e-5,4.911e-5,9.303e-6,7.292e-6,6.507e-6
T,2009,05,06,15,56,34 D,NBXX,380,1.041e-4,7.743e-5,5.073e-5,9.635e-6,7.639e-6,6.867e-6
T,2009,05,06,15,57,34 D,NBXX,320,1.027e-4,7.628e-5,4.938e-5,9.491e-6,7.596e-6,6.489e-6
T,2009,05,06,15,58,34 D,NBXX,260,1.014e-4,7.490e-5,4.852e-5,9.352e-6,7.325e-6,6.657e-6
T,2009,05,06,15,59,34 D,NBXX,200,1.010e-4,7.408e-5,4.763e-5,9.408e-6,7.383e-6,6.794e-6

Is that the desired output?
 
  • #3
Jeez, I would have just opened the file in Word, then done a Replace of |pD (the linebreak character) with ,D then saved out as .txt
 
  • #4
DaveC426913 said:
Jeez, I would have just opened the file in Word, then done a Replace of |pD (the linebreak character) with ,D then saved out as .txt

The easiest way depends what tools you have. If it's a "one off" task, it doesn't matter much if it takes 1 sec or 100 sec to do it, compared with being sure that you did what you wanted to do.

DaveC's solution might be the best for DaveC, because (1) he already has Word and (2) he can remember Microsoft's pointlessly arcane (IMHO) abbreviations for regular expressions and non-printable characters.

Doing it with sed (or several other unix tools, or a good programmer's text editor) is just as trivially simple if you already have some of those tools and you know how to use them. .
 
  • #5
jhae2.718: Yes, that is the desired output. It worked with 3 out of the 5 files... the other ones turned out like this:

Code: 
T,2009,08,18,15,41,28
 D,ZBXX,420,3.972e-5,2.358e-5,3.176e-5,1.940e-5,1.304e-5,2.451e-5
T,2009,08,18,15,42,28
 D,ZBXX,360,3.922e-5,2.326e-5,3.163e-5,1.932e-5,1.300e-5,2.447e-5
T,2009,08,18,15,43,28
 D,ZBXX,300,3.886e-5,2.296e-5,3.147e-5,1.921e-5,1.295e-5,2.447e-5
T,2009,08,18,15,44,28
 D,ZBXX,240,3.857e-5,2.273e-5,3.131e-5,1.926e-5,1.295e-5,2.448e-5

Any reason as to why, and how to fix it?

DaveC426913: AlephZero is right. Each of my files is hundreds of thousands of lines (it's basically 2 lines for every minute of the day for a whole month). If I had pasted that into a Word file, that would easily more than 500 pages. I don't think Word would like that (it would be way too slow). Although sed can be slow at times, it is still much, much faster than Word.
 
  • #6
Sam032789 said:
DaveC426913Each of my files is hundreds of thousands of lines

Ah, yes, well specifying number and size of files in your OP would certainly get you higher quality answers off-the-bat. :wink:
Hello! I have a file ...
 
  • #7
Hmm. I guess I don't see the point in specifying how many lines. Whether it's 5 or 5 million, the operation in sed is essentially the same.
 
  • #8
Are all the files formatted the same initially?
 
  • #9
I thought they were. They look identical to the files that worked. I had to download the data from a website, and it's quite possible they are different in some way I cannot see for these two months.
 
  • #10
You started by saying "my file" and then changed to "each of my files".

A decent programmer's editor will let you open a few hundred files all at once, do the same edit(s) to all of them, and then "save all"...

And so will the Unix command line, of course.
 
  • #11
Yes... but what if the files that look the same are different? This is my problem now. The last two files are different.

I had no problem duplicating the commands and changing one character to operate on different files. I thought all the files were the same. Now I know that they are not for some reason.

I'm just not sure the reason was for posting your last post, AlephZero.
 
  • #12
Problem is solved. My problem in the last two files was that I also had \r's and \n's at the end of each line, instead of just the \n for the other 3 files. If anyone is curious, this is the code I used (and it worked perfectly):

Code: 
sed 's/\r//; /^T/ {N; s/\n/ /}' <input.txt >output.txt
 
  • #13
Those must have been written on Windows. Unix uses \n as a line terminator, Windows does \r\n
 
  • #14
Oh, I see. Thanks for the explanation. I was wondering why this was so!

Glad everything worked out in the end :)
 
  • #15
For further reference,
Code: 
Line Endings
-------------------------------------------------
Windows                       \r\n        (CR LF)
Unix/Linux/Mac OS X           \n          (LF)
Mac OS (before OS X)          \r          (CR)
CR is a carriage return, LF a line feed.
 

Related to Editing Text Files - Easiest Way To Merge Every Other Line

1. What is the easiest way to merge every other line in a text file?

The easiest way to merge every other line in a text file is by using a text editor or a command line tool. These tools allow you to open the text file and edit the lines as needed.

2. Can I merge every other line in a text file using a specific delimiter?

Yes, you can merge every other line in a text file using a specific delimiter. This can be done by using a find and replace function in a text editor or by using a command line tool with the appropriate options.

3. How can I automate the process of merging every other line in a large text file?

You can automate the process of merging every other line in a large text file by writing a script or using a program specifically designed for this task. This will save you time and effort, especially when dealing with large files.

4. Is it possible to merge every other line in a text file without altering the original file?

Yes, it is possible to merge every other line in a text file without altering the original file. This can be done by using a program or script that creates a new file with the merged lines, leaving the original file intact.

5. Are there any risks involved in merging every other line in a text file?

There are some potential risks involved in merging every other line in a text file, such as accidentally deleting important information or altering the file in a way that renders it unusable. It is always recommended to make a backup of the original file before making any changes.

Hot Threads

Recent Insights

Back
Top