Python: turns string into array

Question

I have a code and am unable to append a variable that was a string, to an array to set of arrays My code:

import face_recognition
import numpy as np
a = face_recognition.load_image_file('C:\\Users\zivsi\OneDrive\תמונות\סרט צילום\WIN_20191115_10_32_24_Pro.jpg') # my picture 1
a_encodings = face_recognition.face_encodings(a)[0]
b = face_recognition.load_image_file('C:\\Users\zivsi\OneDrive\תמונות\סרט צילום\WIN_20191115_09_48_56_Pro.jpg') # my picture 2
b_encodings = face_recognition.face_encodings(b)[0]
unknown = face_recognition.load_image_file('C:\\Users\zivsi\OneDrive\תמונות\סרט צילום\WIN_20191117_16_19_11_Pro.jpg')
unknown_encodings = face_recognition.face_encodings(unknown)[0]
print(type(b_encodings)) # This shows that the variable is an array type
b_encodings = str(b_encodings) # I make the array variable, a string
b_encodings = np.array(b_encodings) # I'm trying to turn the string back into the array
print(type(b_encodings)) # It writes that the variable really turned back into an array
results = face_recognition.compare_faces([a_encodings, b_encodings], unknown_encodings, tolerance=0.4) # Here's the problem, it doesn't read it as an array and displays an error
print(results)

• jlewkovich: Adding the error you're getting would help others debug the issue.

Answer 1

I have no experience with numpy but here's my guess for what is happening.

1. b_encodings is initially an array like [1, 2, 3]
2. Then you set b_encodings to the string of itself which is "[1, 2, 3]"
3. You ask for np.array of this, but in the NumPy documentation it says this argument should be array-like. The string you are giving it is array-like, since

list("[1, 2, 3]") == ['[', '1', ',', ' ', '2', ',', ' ', '3', ']']

So the final b_encodings is now this array of the components of an array as a string.

[1, 2, 3] !== ['[', '1', ',', ' ', '2', ',', ' ', '3', ']']

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I don't understand why you ever want to convert the actual array data into a string, only to convert it back later.

If you want to print it, it will probably get converted automatically to a string. If not, you can convert it inline. If you really need a variable with it as a string, you can create a new one.

If you need to store the array (in a file), you could dump it with pickle or write one line per item to a file.

• Zivv: I want to make b_encodings to string because, i want to save this in file
• Zivv: So... i didnt understand what you suggesting
• blueteeth: You could use pickle to dump the object to file. Or write a file with one line per item. Assuming you can convert string items to their desired values, you could do f.readlines() to get the array back.
• Zivv: I need to replace " " " ?
• Zivv: I mean, delet the " from the valiue