[FIXED] The view function did not return a valid response. The function either returned None or ended without a return statement

Issue

I try return the result of function np.correlate, using flask and numpy

  from flask import Flask
import numpy as np
app = Flask(__name__)
@app.route("/")
def corelation():
    # 1 2 3 8 9 7 3 12 65 45 26 33
     firstArray = np.loadtxt("C:\\Users\\user\\source\\repos\\CorelationApplication\\firstfile.txt")
    # 43 32 23 45 65 99 77 11 20 32 65 11 12
     secondArray = np.loadtxt("C:\\Users\\user\\source\\repos\\CorelationApplication\\secondfile.txt")
     corr = np.correlate(firstArray,secondArray, 'full')  
     result = print (corr)  
     # 1.2000e+01 3.5000e+01 1.2300e+02 2.9100e+02 4.7500e+02 8.5000e+02
     # 1.2000e+01 3.5000e+01 1.2300e+02 2.9100e+02 4.7500e+02 8.5000e+02
     # 1.2000e+01 3.5000e+01 1.2300e+02 2.9100e+02 4.7500e+02 8.5000e+02
     # 1.2000e+01 3.5000e+01 1.2300e+02 2.9100e+02 4.7500e+02 8.5000e+02
     return result
if __name__ == "__main__":
    app.run(debug = True)

I getting this message:The view function did not return a valid response. The function either returned None or ended without a return statement

Solution

If all you need is a textual representation of an np.array, the simplest way to get there is

from flask import make_response

...
corr = np.correlate(firstArray,secondArray, 'full')
response = make_response(str(corr), 200)
response.mimetype = 'text/plain'
return response

Answered By - Dave W. Smith