我想在 csv 文件中写入，它只写入最后一个值（我打印该值并且它有效，但在 csv 中没有）

Question

for box in boxes:
    (x, y, w, h) = [int(v) for v in box]
    a = x + w
    b = y + h
    cv2.rectangle(im, (x, y), (a, b), (0, 255, 0), 2)
    with open('employee_file.csv', mode='w', newline='') as employee_file:
        employee_writer = csv.writer(employee_file, delimiter=',', quotechar='"',
                                     quoting=csv.QUOTE_MINIMAL)

        employee_writer.writerow(str[x,a])

My code must write all the values in x, y, b but it writes only one line, the last.

Answer 1

You are supposed to use append mode for writing to your file in a for loop. Otherwise, you will end up with only the last x,y,b values in your data.

with open('employee_file.csv', mode='a', newline='')

The line above will solve your issue. Use mode 'a' . You're opening the file in write mode . Write mode over-writes the previous content in the file. Therefore, every time your code opens the file, it clears the data in it.