what is none in python code example

Example 1: None python

# The None keyword is effectively the same as null
# Functions without a return will return None

>>> def has_no_return():
...     pass
>>> has_no_return()
>>> print(has_no_return())
None

# Often, you’ll use None as part of a comparison.
# One example is when you need to check and see if some result or parameter is None.

>>> import re
>>> match = re.match(r"Goodbye", "Hello, World!")
>>> if match is None:
...     print("It doesn't match.")
"It doesn't match."

Example 2: is not none in python

>>> x = None 
... if x: 
...     print 'if x' 
... if x is not None: 
...     print 'if x is not None'

Example 3: how to save a nonetype as a function in python

import sys, math, Image
import os

def Distance(p1,p2):
  dx = p2[0] - p1[0]
  dy = p2[1] - p1[1]
  return math.sqrt(dx*dx+dy*dy)

def ScaleRotateTranslate(image, angle, center = None, new_center = None, scale = None, resample=Image.BICUBIC):
  if (scale is None) and (center is None):
    return image.rotate(angle=angle, resample=resample)
  nx,ny = x,y = center
  sx=sy=1.0
  if new_center:
    (nx,ny) = new_center
  if scale:
    (sx,sy) = (scale, scale)
  cosine = math.cos(angle)
  sine = math.sin(angle)
  a = cosine/sx
  b = sine/sx
  c = x-nx*a-ny*b
  d = -sine/sy
  e = cosine/sy
  f = y-nx*d-ny*e
  return image.transform(image.size, Image.AFFINE, (a,b,c,d,e,f), resample=resample)

def CropFace(image, eye_left=(0,0), eye_right=(0,0), offset_pct=(0.2,0.2), dest_sz = (70,70)):
  # calculate offsets in original image
  offset_h = math.floor(float(offset_pct[0])*dest_sz[0])
  offset_v = math.floor(float(offset_pct[1])*dest_sz[1])
  # get the direction
  eye_direction = (eye_right[0] - eye_left[0], eye_right[1] - eye_left[1])
  # calc rotation angle in radians
  rotation = -math.atan2(float(eye_direction[1]),float(eye_direction[0]))
  # distance between them
  dist = Distance(eye_left, eye_right)
  # calculate the reference eye-width
  reference = dest_sz[0] - 2.0*offset_h
  # scale factor
  scale = float(dist)/float(reference)
  # rotate original around the left eye
  image = ScaleRotateTranslate(image, center=eye_left, angle=rotation)
  # crop the rotated image
  crop_xy = (eye_left[0] - scale*offset_h, eye_left[1] - scale*offset_v)
  crop_size = (dest_sz[0]*scale, dest_sz[1]*scale)
  image = image.crop((int(crop_xy[0]), int(crop_xy[1]), int(crop_xy[0]+crop_size[0]), int(crop_xy[1]+crop_size[1])))
  # resize it
  image = image.resize(dest_sz, Image.ANTIALIAS)
  return image

def readFileNames():
    try:
        inFile = open('E:\\Project_Face\\Projects\\image_data.csv')
    except:
        raise IOError('There is no file named path_to_created_csv_file.csv in current directory.')
        return False

    picPath = []
    picIndex = []
    for line in inFile.readlines():
        if line != '':

            fields = line.rstrip().split(';')
            picPath.append(fields[0])
            picIndex.append(int(fields[1]))

    return (picPath, picIndex)


if __name__ == "__main__":
  [images, indexes]=readFileNames()
if not os.path.exists("modified"):
    os.makedirs("modified")
for img in images:
    image =  Image.open(img)
    CropFace(image, eye_left=(182,264), eye_right=(304,265), offset_pct=(0.1,0.1), dest_sz=(200,200)).save(".\\modified\\"+img.rstrip().split('\\')[5]+"_10_10_200_200.jpg")
    CropFace(image, eye_left=(182,264), eye_right=(304,265), offset_pct=(0.2,0.2), dest_sz=(200,200)).save(".\\modified\\"+img.rstrip().split('\\')[5]+"_20_20_200_200.jpg")
    CropFace(image, eye_left=(182,264), eye_right=(304,265), offset_pct=(0.3,0.3), dest_sz=(200,200)).save(".\\modified\\"+img.rstrip().split('\\')[5]+"_30_30_200_200.jpg")
    CropFace(image, eye_left=(182,264), eye_right=(304,265), offset_pct=(0.2,0.2)).save("_20_20_70_70.jpg").save(".\\modified\\"+img.rstrip().split('\\')[5]+"_20_20_70_70.jpg")