I have a CSV file from which I am reading parameters.
I want using Flexible File Writer to write the extracted values I am able to write Available Fields but I want to write the variables I am reading from CSV as well as extracted response but extracted values are not being written also the headers and values are written in the single cell I want those to be written in separate cells.
Related
I have finally managed to split a large file and reaggregate into smaller (but still very large files)
At the end of the writing I have the count of records in each file. This needs to be added to each of the smaller files as a header.
What is the best way to accomplish this in a performant way ?
Possibilities I considered:
Write a file with each header as the split data files are being generated.
At the end match up the header and the data file and write concatenate it.
I am running into issues how to read the file in a non polling way and how to trigger the concat phase. This would require re-writing the entire big files
keep file headers in a message header or exchange and when all files are written, read all the files from the directory, find a matching header file and add it to output.
This would require re-writing the entire big files
Add a dummy header with placeholders for the count data and somehow modify the data files in place....
this seems most performant but not sure how to do this
Header: 3 records
a
b
c
How to use __StringFromFile function with Beanshell Preprocessor
For example, i have a text file which contains comma separated values as in the attachment.
I want to read data from these file and assign to variables.
If you want to read complete file and store it into one variable than paste
${__FileToString(C:/path,,Variable_Name)}
command in beanshell preprocessor and pass ${Variable_Name} where you want to use it
But
If you want to read line by line than you can choose __StringFromFile function, you can also use csv data set config to fulfill you requirement, just change delimiter , to some other delimiter like ~ (As you mentioned your values are separated by comma). It will capture complete line and store into one variable
Refer this link for detailed information on Jmeter function
So I have to write a C program to read data from .csv files supplied to me by multiple users, into matrices on which I will perform some operations (like matrix addition, multiplication with necessary conditions on dimensions, etc.) and print these matrices (or the output data) in to .csv files again.
I also need to dynamically allocate memory to my matrices.
Now, I have zero background in dealing with .csv files. I do not at all know the required code to read a .csv file or write into a .csv file. I have searched for long on the Internet but surprisingly I have not found any program that teaches how to deal with .csv files from the elementary level.
I am lost on this and need a lot of guidance, maybe a sample, fully well-written C program as I need a comprehensive example to begin with.
A CSV file is just a plain ASCII text file that contains a grid of values. Think of the file as a set of rows in a database table where each line in the file represents one record and the order of the data in each line is identical. Each item of data is separated using a comma character (hence the name). So to read the file:-
open file
until the end of the file
read line into a string
split the string into sub strings where ',' is the dilimiter
parse each sub string
Since there is no formatting information in a CSV file, if the data in each value consists of a string, then what do you do if the value has a comma in it? For reading numbers that is not a problem for you.
You could read the file in several passes, the first to determine the amount of data there is (number of columns, number of rows, etc) and the second to actually read the data.
Writing the CSV is quite simple:-
open file
for each record to write
for each element to write
write element
if not last element
write a comma
write a new line
I want to send a file as an email attachment, but at present there is an email filter that prevents that. Is there a simple method or library to encapsulate a file of any length inside an uncompressed ZIP file? I'd like to avoid adding an actual ZIP library that compresses, if I can. For one thing, the file I'm sending is already compressed.
The zip format has a stored method (method 0) that would allow you to simply enclose the file in the appropriate headers. See the PKWare appnote.txt for a description of the format. You would need to calculate the CRC-32 of the data to include in the headers.
How can I go back to the very beginning of a csv file and add rows?
(I'm printing to a CSV file from C using fprintf(). At the end of printing thousands of rows (5 columns) of data, I would like to go back to the top of the file and insert some dynamic header data (based on how things went printing everything). )
Thank You.
Due to the way files are structured, this is more or less impossible. In order to accomplish what you want:
write csv data to file1
write header to file2
copy contents of file1 to file2
delete file1
Or you can hold the csv data in ram and write it to file after you're finished processing and know the header.
Another option is to set aside a certain number of bytes for the header, which will work much faster for large files at minimal space cost. Since the space is allocated in the file at the start of the write, there aren't any issues going back and filling it in. Reopen the file as random access ("r+"), which points to the top of the file by default, write header, and close.
The simplest way would be to simply store the entire contents of the file in memory until you are finished, write out the header, and then write out the rest of the file.
If memory is an issue and you can't safely store the entire file in memory, or just don't want to, then you could write out the bulk of the CSV data to a temporary file, then when you are finished, write the header out to the primary file, and copy the data from the temporary file to the primary file in a loop.
If you wanted to be fancy, after writing the main CSV data out to the primary file, you could loop through the file from the beginning, read into memory the data that you're about to overwrite with the header, then write the header over top of that data, and so forth, read each chunk into memory, overwrite it with the previous one until you reach the end and append the final chunk. In this way you "insert" data at the beginning, my moving the rest of the file down. I really wouldn't recommend this as it will mostly just add complexity without much benefit, unless there is a specific reason you can't do something simpler like using a temporary file.
I think that is not possible. Probably the easiest way would be to write the output to a temporary file, then create the data you need as the dynamic header, write them to the target file and append the previously created temporary file.
write enough blank spaces in the first line
write data
seek(0)
write header - last column will be padded with spaces