在 csv 文件中写入混合数据行

Question

I want to write rows in a.csv file along with headers where each row has both numeric value and strings. Following are the headers:

Here only the "filename" and "class" are of string type. The rest of the columns are numerical. Header should be written only once and the rows to be appended one by one. There should be no blank newline in between rows.

So I did the following:

• Initially I wrote the headers separately:

   fields = ["filename", "width", "height", "class", "xmin", "ymin", "xmax", "ymax"] with open(csv_file_dir, 'w') as csvfile: # creating a csv writer object csvwriter = csv.writer(csvfile) # writing the fields csvwriter.writerow(fields) csvfile.close()

• Therefore inside a loop (where I am producing each of the data-rows) I used the similar code to append each of the rows like this (I used type-casting to convert the integers to string otherwise it was producing error like: "...iterable expected, not int"):

   rows = [str(img_SN), str(w), str(h), "eye", str(relt[0]), str(relt[1]), str(rerb[0]), str(rerb[1])] # data row # writing to csv file with open(csv_file_dir, 'a') as csvfile: # creating a csv writer object csvwriter = csv.writer(csvfile, delimiter = ',') # writing the data rows csvwriter.writerows(rows) csvfile.close()

But it is giving totally undesired output. For example, for a sample data-row the output is as follow:

['0.jpg', '464', '350', 'eye', '107', '119', '133', '145']

Which is being written in the file as follow:

ie, each of the characters is being spited and moreover it is going to newline automatically.

But the desired output be like:

Considering two sample rows:

['0.jpg', '464', '350', 'eye', '107', '119', '133', '145']

['1.jpg', '768', '576', 'eye', '131', '176', '257', '302']

The output I need like this:

How to achieve this?

Answer 1

Use writerow instead of writerows if you want to write only one row at a time.