Merge pull request #7597 from hugovk/comprehensions

Use list comprehensions to create transformed lists

Author: radarhere

Tests/test_file_apng.py

@@ -356,9 +356,7 @@ def test_apng_save(tmp_path):
  assert im.getpixel((64, 32)) == (0, 255, 0, 255)
 
  with Image.open("Tests/images/apng/single_frame_default.png") as im:
- frames = []
- for frame_im in ImageSequence.Iterator(im):
- frames.append(frame_im.copy())
+ frames = [frame_im.copy() for frame_im in ImageSequence.Iterator(im)]
  frames[0].save(
  test_file, save_all=True, default_image=True, append_images=frames[1:]
  )

src/PIL/FpxImagePlugin.py

@@ -97,16 +97,15 @@ def _open_index(self, index=1):
 
  s = prop[0x2000002 | id]
 
- colors = []
  bands = i32(s, 4)
  if bands > 4:
  msg = "Invalid number of bands"
  raise OSError(msg)
- for i in range(bands):
- # note: for now, we ignore the "uncalibrated" flag
- colors.append(i32(s, 8 + i * 4) & 0x7FFFFFFF)
 
- self._mode, self.rawmode = MODES[tuple(colors)]
+ # note: for now, we ignore the "uncalibrated" flag
+ colors = tuple(i32(s, 8 + i * 4) & 0x7FFFFFFF for i in range(bands))
+
+ self._mode, self.rawmode = MODES[colors]
 
  # load JPEG tables, if any
  self.jpeg = {}

src/PIL/Image.py

@@ -1288,9 +1288,9 @@ def filter(self, filter):
  if self.im.bands == 1 or multiband:
  return self._new(filter.filter(self.im))
 
- ims = []
- for c in range(self.im.bands):
-  ims.append(self._new(filter.filter(self.im.getband(c))))
+ ims = [
+  self._new(filter.filter(self.im.getband(c))) for c in range(self.im.bands)
+ ]
  return merge(self.mode, ims)
 
  def getbands(self):
@@ -1339,10 +1339,7 @@ def getcolors(self, maxcolors=256):
  self.load()
  if self.mode in ("1", "L", "P"):
  h = self.im.histogram()
- out = []
- for i in range(256):
- if h[i]:
- out.append((h[i], i))
+ out = [(h[i], i) for i in range(256) if h[i]]
  if len(out) > maxcolors:
  return None
  return out
@@ -1383,10 +1380,7 @@ def getextrema(self):
 
  self.load()
  if self.im.bands > 1:
- extrema = []
- for i in range(self.im.bands):
- extrema.append(self.im.getband(i).getextrema())
- return tuple(extrema)
+ return tuple(self.im.getband(i).getextrema() for i in range(self.im.bands))
  return self.im.getextrema()
 
  def _getxmp(self, xmp_tags):

src/PIL/ImageCms.py

@@ -787,11 +787,8 @@ def getProfileInfo(profile):
  # info was description \r\n\r\n copyright \r\n\r\n K007 tag \r\n\r\n whitepoint
  description = profile.profile.profile_description
  cpright = profile.profile.copyright
- arr = []
- for elt in (description, cpright):
- if elt:
- arr.append(elt)
- return "\r\n\r\n".join(arr) + "\r\n\r\n"
+ elements = [element for element in (description, cpright) if element]
+ return "\r\n\r\n".join(elements) + "\r\n\r\n"
 
  except (AttributeError, OSError, TypeError, ValueError) as v:
  raise PyCMSError(v) from v

src/PIL/ImageOps.py

@@ -557,9 +557,7 @@ def invert(image):
  :param image: The image to invert.
  :return: An image.
  """
- lut = []
- for i in range(256):
- lut.append(255 - i)
+ lut = list(range(255, -1, -1))
  return image.point(lut) if image.mode == "1" else _lut(image, lut)
 
 
@@ -581,10 +579,8 @@ def posterize(image, bits):
  :param bits: The number of bits to keep for each channel (1-8).
  :return: An image.
  """
- lut = []
  mask = ~(2 ** (8 - bits) - 1)
- for i in range(256):
- lut.append(i & mask)
+ lut = [i & mask for i in range(256)]
  return _lut(image, lut)
 
 

src/PIL/ImagePalette.py

@@ -200,21 +200,15 @@ def raw(rawmode, data):
 
 
 def make_linear_lut(black, white):
- lut = []
  if black == 0:
- for i in range(256):
- lut.append(white * i // 255)
- else:
- msg = "unavailable when black is non-zero"
- raise NotImplementedError(msg) # FIXME
- return lut
+ return [white * i // 255 for i in range(256)]
+
+ msg = "unavailable when black is non-zero"
+ raise NotImplementedError(msg) # FIXME
 
 
 def make_gamma_lut(exp):
- lut = []
- for i in range(256):
- lut.append(int(((i / 255.0) ** exp) * 255.0 + 0.5))
- return lut
+ return [int(((i / 255.0) ** exp) * 255.0 + 0.5) for i in range(256)]
 
 
 def negative(mode="RGB"):
@@ -226,9 +220,7 @@ def negative(mode="RGB"):
 def random(mode="RGB"):
  from random import randint
 
- palette = []
- for i in range(256 * len(mode)):
- palette.append(randint(0, 255))
+ palette = [randint(0, 255) for _ in range(256 * len(mode))]
  return ImagePalette(mode, palette)
 
 

src/PIL/ImageQt.py

@@ -103,12 +103,10 @@ def align8to32(bytes, width, mode):
  if not extra_padding:
  return bytes
 
- new_data = []
- for i in range(len(bytes) // bytes_per_line):
- new_data.append(
- bytes[i * bytes_per_line : (i + 1) * bytes_per_line]
- + b"\x00" * extra_padding
- )
+ new_data = [
+ bytes[i * bytes_per_line : (i + 1) * bytes_per_line] + b"\x00" * extra_padding
+ for i in range(len(bytes) // bytes_per_line)
+ ]
 
  return b"".join(new_data)
 
@@ -131,15 +129,11 @@ def _toqclass_helper(im):
  format = qt_format.Format_Mono
  elif im.mode == "L":
  format = qt_format.Format_Indexed8
- colortable = []
- for i in range(256):
- colortable.append(rgb(i, i, i))
+ colortable = [rgb(i, i, i) for i in range(256)]
  elif im.mode == "P":
  format = qt_format.Format_Indexed8
- colortable = []
  palette = im.getpalette()
- for i in range(0, len(palette), 3):
- colortable.append(rgb(*palette[i : i + 3]))
+ colortable = [rgb(*palette[i : i + 3]) for i in range(0, len(palette), 3)]
  elif im.mode == "RGB":
  # Populate the 4th channel with 255
  im = im.convert("RGBA")

src/PIL/ImageStat.py

@@ -59,14 +59,10 @@ def minmax(histogram):
  x = max(x, i)
  return n, x # returns (255, 0) if there's no data in the histogram
 
- v = []
- for i in range(0, len(self.h), 256):
- v.append(minmax(self.h[i:]))
- return v
+ return [minmax(self.h[i:]) for i in range(0, len(self.h), 256)]
 
  def _getcount(self):
  """Get total number of pixels in each layer"""
-
  return [sum(self.h[i : i + 256]) for i in range(0, len(self.h), 256)]
 
  def _getsum(self):
@@ -93,11 +89,7 @@ def _getsum2(self):
 
  def _getmean(self):
  """Get average pixel level for each layer"""
-
- v = []
- for i in self.bands:
- v.append(self.sum[i] / self.count[i])
- return v
+ return [self.sum[i] / self.count[i] for i in self.bands]
 
  def _getmedian(self):
  """Get median pixel level for each layer"""
@@ -116,28 +108,18 @@ def _getmedian(self):
 
  def _getrms(self):
  """Get RMS for each layer"""
-
- v = []
- for i in self.bands:
- v.append(math.sqrt(self.sum2[i] / self.count[i]))
- return v
+ return [math.sqrt(self.sum2[i] / self.count[i]) for i in self.bands]
 
  def _getvar(self):
  """Get variance for each layer"""
-
- v = []
- for i in self.bands:
- n = self.count[i]
- v.append((self.sum2[i] - (self.sum[i] ** 2.0) / n) / n)
- return v
+ return [
+ (self.sum2[i] - (self.sum[i] ** 2.0) / self.count[i]) / self.count[i]
+ for i in self.bands
+ ]
 
  def _getstddev(self):
  """Get standard deviation for each layer"""
-
- v = []
- for i in self.bands:
- v.append(math.sqrt(self.var[i]))
- return v
+ return [math.sqrt(self.var[i]) for i in self.bands]
 
 
 Global = Stat # compatibility

src/PIL/JpegImagePlugin.py

@@ -233,9 +233,7 @@ def SOF(self, marker):
  # fixup icc profile
  self.icclist.sort() # sort by sequence number
  if self.icclist[0][13] == len(self.icclist):
- profile = []
- for p in self.icclist:
- profile.append(p[14:])
+ profile = [p[14:] for p in self.icclist]
  icc_profile = b"".join(profile)
  else:
  icc_profile = None # wrong number of fragments

src/PIL/MicImagePlugin.py

@@ -51,10 +51,11 @@ def _open(self):
  # find ACI subfiles with Image members (maybe not the
  # best way to identify MIC files, but what the... ;-)
 
- self.images = []
- for path in self.ole.listdir():
- if path[1:] and path[0][-4:] == ".ACI" and path[1] == "Image":
- self.images.append(path)
+ self.images = [
+ path
+ for path in self.ole.listdir()
+ if path[1:] and path[0][-4:] == ".ACI" and path[1] == "Image"
+ ]
 
  # if we didn't find any images, this is probably not
  # an MIC file.