如何通过python字典循环保存每个输出数据

Question

Today i found problem in my python dict. I need to collect all output data from loop and write it in json file. Process of writing works well, but, as result, inside json file only one, last output. How i should fix part of my code with dictionary? Here is code:

def classify(sess, label_list, softmax_output, coder, images, image_file):

print('Running file %s' % image_file)
image_batch = make_batch(image_file, coder, not FLAGS.single_look)
batch_results = sess.run(softmax_output, feed_dict={images:image_batch.eval()})
output = batch_results[0]
batch_sz = batch_results.shape[0]
for i in range(1, batch_sz):
    output = output + batch_results[i]

output /= batch_sz
best = np.argmax(output)
best_choice = (label_list[best], output[best])
Guess = 'Guess @ 1 %s, prob = %.2f' % best_choice
print('Guess @ 1 %s, prob = %.2f' % best_choice)
faces_pred = dict()
faces_pred =  {"face_pred": Guess}
with open('pred.json', 'w') as fp:
    json.dump( faces_pred, fp)

nlabels = len(label_list)
if nlabels > 2:
    output[best] = 0
    second_best = np.argmax(output)

    print('Guess @ 2 %s, prob = %.2f' % (label_list[second_best], output[second_best]))
return best_choice

I am interesting only in all output's of Guess 1! Thank you for your time :3

UPD--------- Inside json file, after run my program, have this output:

{"face_pred": "Guess @ 1 (60, 100), prob = 0.75"}

That's correct, but only for one face (i have 3+ Guess @ 1). It's not adding new data in json file, just rewriting it!

UPD2-------- How it looks like is console:

• Running file ./frontal-face-1.jpg
• Running multi-cropped image
• Guess @ 1 (60, 100), prob = 0.95
• Guess @ 2 (4, 6), prob = 0.02
• Running file ./frontal-face-2.jpg
• Running multi-cropped image
• Guess @ 1 (60, 100), prob = 0.75
• Guess @ 2 (38, 43), prob = 0.12
• ubuntu@ubuntu122:~/roman/IWAdector$

Answer 1

with your comments i now understand your problem... you open your file like this:

with open('pred.json', 'w') as fp:
    json.dump( faces_pred, fp)

and that rewrites the entire file each time, so you only get the last result there

you could do this instead:

with open('pred.json', 'a') as fp:
    data_to_write = json.dumps(faces_pred)
    fp.write(faces_pred + '\n')

notice 2 things i did here:

1. I opened the file with the 'a' flag and not 'w', that is used for appending to the end of the file each time instead of rewriting the file

2. I used json.dumps instead of json.dump to produce a string, and then wrote that string (appended it) to the file, with \\n at the end to ensure it will break the line after each time