Pytesseract loop error

I'm trying to loop pytesseract code to convert multiple images(18) into strings and name the output in sequece. tried to rearrange and replace the loop position more errors accur.

import cv2
import numpy as np
import pytesseract
from PIL import Image

src_path = "/home/pi/Desktop/"

def get_string(img_path):

for n in range(0,18):

n=n+1

img = cv2.imread(img_path)

img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

kernel = np.ones((1, 1), np.uint8)
img = cv2.dilate(img, kernel, iterations=1)
img = cv2.erode(img, kernel, iterations=1)

cv2.imwrite(src_path + "removed_noise"+ n +".png",img)
cv2.imwrite(src_path +"thres"+ n +".png", img)

result = pytesseract.image_to_string(Image.open(src_path + "thres"+ n +".png"))

return result

print (get_string(src_path +"sample"+ str(n) +".jpeg"))
print ("------ Done -------")


it returns an error

Traceback (most recent call last):
File "/home/pi/Desktop/imagetostring.py", line 29, in <module>
print (get_string(src_path +"sample"+ str(n) +".jpeg"))
NameError: name 'n' is not defined


1 Answer
1

n is a local variable of the get_string function. With your indentation, the print statement is outside this function, so the variable is out of scope, hence the error.

n

get_string

print

Simple code to explain scopes of local variables:

def someFunction(N):
print(myLocal) # ERROR: myLocal not defined yet.
for myLocal in range(1,N):
print(myLocal) # OK
print(myLocal) # OK

print(myLocal) # ERROR (your case): myLocal can't be accessed outside someFunction.
# It doesn't even exist while someFunction is not being executed.


NameError

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