Keras model.summary() object to string

With my version of Keras (2.0.6) and Python (3.5.0), this works for me:

# Create an empty model
from keras.models import Sequential
model = Sequential()

# Open the file
with open(filename + 'report.txt','w') as fh:
    # Pass the file handle in as a lambda function to make it callable
    model.summary(print_fn=lambda x: fh.write(x + '\n'))

This outputs the following lines to the file:

_________________________________________________________________
Layer (type)                 Output Shape              Param #   
=================================================================
Total params: 0
Trainable params: 0
Non-trainable params: 0
_________________________________________________________________

For me, this worked to just get the model summary as a string:

stringlist = []
model.summary(print_fn=lambda x: stringlist.append(x))
short_model_summary = "\n".join(stringlist)
print(short_model_summary)

And if you want to write to a log:

import logging
logger = logging.getLogger(__name__)

model.summary(print_fn=logger.info)

I understand the OP has already accepted winni2k's answer, but since the question title actually implies saving the outputs of model.summary() to a string, not a file, the following code might help others who come to this page looking for that (like I did).

The code below was run using TensorFlow 1.12.0, which comes with Keras 2.1.6-tf on Python 3.6.2.

from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense, Activation
import io

# Example model
model = Sequential([
    Dense(32, input_shape=(784,)),
    Activation('relu'),
    Dense(10),
    Activation('softmax'),
])

def get_model_summary(model):
    stream = io.StringIO()
    model.summary(print_fn=lambda x: stream.write(x + '\n'))
    summary_string = stream.getvalue()
    stream.close()
    return summary_string

model_summary_string = get_model_summary(model)

print(model_summary_string)

Which yields (as a string):

_________________________________________________________________
Layer (type)                 Output Shape              Param #   
=================================================================
dense (Dense)                (None, 32)                25120     
_________________________________________________________________
activation (Activation)      (None, 32)                0         
_________________________________________________________________
dense_1 (Dense)              (None, 10)                330       
_________________________________________________________________
activation_1 (Activation)    (None, 10)                0         
=================================================================
Total params: 25,450
Trainable params: 25,450
Non-trainable params: 0
_________________________________________________________________

I stumbled upon the same problem as well! There are two possible workarounds:

Use to_json() method of the model

summary = str(model.to_json())

This is your case above.

Otherwise use the ascii method from keras_diagram

from keras_diagram import ascii
summary = ascii(model)

It's not the best way to do it but one thing you can do is to redirect stdout:

orig_stdout = sys.stdout
f = open('out.txt', 'w')
sys.stdout = f
print(model.summary())
sys.stdout = orig_stdout
f.close()

see "How to redirect 'print' output to a file using python?"

One option, although not an exact replacement for model.summary, is to export a model's configuration using model.get_config(). From the docs:

model.get_config(): returns a dictionary containing the configuration of the model. The model can be reinstantiated from its config via: config = model.get_config() model = Model.from_config(config) # or, for Sequential: model = Sequential.from_config(config)

I had this same problem. @Pasa's answer was very useful but I thought I would post a more minimal example: it's a reasonable assumption that you already have a Keras model at this point.

import io

s = io.StringIO()
model.summary(print_fn=lambda x: s.write(x + '\n'))
model_summary = s.getvalue()
s.close()

print("The model summary is:\n\n{}".format(model_summary))

An example of when having this string is useful: if you have a matplotlib plot. You can then use:

plt.text(0, 0.25, model_summary)

https://i.stack.imgur.com/KhIVm.png

As I came here to find a way to log the summary, I wanted to share this little twist to @ajb answer to avoid the INFO: at every line in the log file by using @FAnders answer:

def get_model_summary(model: tf.keras.Model) -> str:
    string_list = []
    model.summary(line_length=80, print_fn=lambda x: string_list.append(x))
    return "\n".join(string_list)

# some code
logging.info(get_model_summary(model)

https://i.stack.imgur.com/lj4zH.png