writing of data from txt-file to .csv file python-CodePudding

I have some lines of test data in a txt-file saved like this:

$PZFM1,A,1,0,0,0,0,0,2,3,008,000,000,201149*6A
$PZFM2,A,1,000,000,000,011*43
$PZFM3,A,1,800*56
$PZFM4,A,1,0000*69

I would like to read it in line by line and write into a csv-file using python. My code so far:

import csv

testdata_name = 'data_test.txt'                                                                         

save_data = open('data.csv','w',newline='', encoding='utf-8')
writer = csv.writer(save_data)

test = open(testdata_name,'r')
 
while 1:     
    line_test = test.readline()
    print("Input: "   line_test)
    writer.writerow(line_test)

with the output like this:

$,P,Z,F,M,1,",",A,",",1,",",0,",",0,",",0,",",0,",",0,",",2,",",3,",",0,0,8,",",0,0,0,",",0,0,0,",",2,0,1,1,4,9,*,6,A,"
"
$,P,Z,F,M,2,",",A,",",1,",",0,0,0,",",0,0,0,",",0,0,0,",",0,1,1,*,4,3,"
"
$,P,Z,F,M,3,",",A,",",1,",",8,0,0,*,5,6,"
"
$,P,Z,F,M,4,",",A,",",1,",",0,0,0,0,*,6,9

However, the data in the csv file does not look one-to-one like that from the txt file and that is actually my goal. What am I doing wrong?

CodePudding user response：

writer.writerow(line_test) expects a List containing the content of the columns of the row you want to write. However, you feed the writerow function with a string (str).

Since a string is an array of character, it creates a column for each character in your line.

To separate your fields (if your fields are separated by a comma), you can use

writer.writerow(line_test.split(","))

This way, the string is first transformed in an array containing with each field.

However, as @Fang said, your file is already a CSV, you might be able to open it with a spreadsheet software after changing the extension

Edit: The quotation marks around the commas are placed in order to differentiate the comma as a delimiter and the comma as a character

CodePudding user response：

test.readline() returns a string, which is a sequence.

Then you do writer.writerow(line_test), which expects a list (of values to separate them with commas) or another sequence. So writerow iterates over line_test (which is a string, so it yields single characters, and writes every character as a value. So you get a comma-separated lines of characters.