Databases
StackOverflow2013
Postsdbo
POIs it possible to append to the first line of an exisiting file?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POIs it possible to append to the first line of an exisiting file?
    primarykey
    data
    text
    <p>I've looked at several of the functions that are able to add text to an existing data file (.csv or .txt) such as write.table, write.lines, or sink.</p> <p>When the append argument =TRUE, the new data is always added after the last existing line of the file. Is it possible to add data to an existing file on first line (below a header)- AKA opposite of append?</p> <p>Given a data frame:</p> <pre><code>DF &lt;- as.data.frame(matrix(seq(20),nrow=5,ncol=4)) colnames(DF) &lt;- c("A", "B", "C", "D") write.table(DF, "DF.csv", row.names=FALSE, sep=",") </code></pre> <p>I can append a new data frame to the last line like this</p> <pre><code>A &lt;- 1 A &lt;- data.frame(A) A$B &lt;- 1 A$C &lt;- 1 A$D &lt;- 1 write.table(A, "DF.csv", row.names=FALSE, sep=",", append=TRUE, col.names=FALSE) </code></pre> <p>Which is close to what I want. But I would really like to have the above line to be added to the first line of the DF.csv (right below the header) like so</p> <pre><code>A B C D 1 1 1 1 1 6 11 16 2 7 12 17 3 8 13 18 4 9 14 19 5 10 15 20 </code></pre> <p>To be clear, I'd not looking to add a row into a data frame within R. I am hoping to add a row to the beginning of a file outside of the R environment. Just as append can be used to add data to the end of an external .csv file, I am hoping to "append" data to the beginning of a .csv file, so that my latest data always comes up in the first row (to avoid scrolling through to the end of a long file to see the most current data). </p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USVinterwoo
    1. USVinterwoo
    plurals
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POIs it possible to append to the first line of an exisiting file?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POIs it possible to append to the first line of an exisiting file?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POIs it possible to append to the first line of an exisiting file?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIn any computer programming language, you can generally assume that text files are fixed and cannot be changed. Think about it like this: a text file is really just one long continuous string of characters. The lines we see are a text editor interpreting one of the characters('\n') in a certain way. What you are asking is if it's possible to insert some characters into that string. How would you do that without overwriting the characters that are already there? If you wanted to replace 3 characters with 3 other characters, you could just overwrite the original 3 characters.
      singulars
      1. POIs it possible to append to the first line of an exisiting file?
      1. US7stud
    2. COYou should search SO for post regarding inserting lines in data.frames
      singulars
      1. POIs it possible to append to the first line of an exisiting file?
      1. US42-
    3. COI came across "R: Insert a vector as a row in data.frame" previously, but my issue has been trying to write/ append a row into a separate .csv file outside of R. Not a data frame within R
      singulars
      1. POIs it possible to append to the first line of an exisiting file?
      1. USVinterwoo
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload