unpack

问题 we can simply use: crc = struct.unpack('>i', data) why people like this: (crc,) = struct.unpack('>i', data) what does the comma mean? 回答1: The first variant returns a single-element tuple: In [13]: crc = struct.unpack('>i', '0000') In [14]: crc Out[14]: (808464432,) To get to the value, you have to write crc[0] . The second variant unpacks the tuple, enabling you to write crc instead of crc[0] : In [15]: (crc,) = struct.unpack('>i', '0000') In [16]: crc Out[16]: 808464432 回答2: the unpack

问题 I'm trying to get an Image's pixel RGB with the PIL Image Library. With this code, I ran into the error: for i in range(width): for j in range(height): r,g,b=(image.getpixel((i,j))) #THIS LINE IS REFERENCED IN ERROR MESSAGE print("leds[",j,"] = CRGB(",r, "," ,g, ",", b, ");") #print pixel colorchange to console del image Why do I get this error? To me, this seems really strange. I input 2 images and it works just fine. However when I have white pixels at a certain position in the image, I get

问题 I'm trying to get an Image's pixel RGB with the PIL Image Library. With this code, I ran into the error: for i in range(width): for j in range(height): r,g,b=(image.getpixel((i,j))) #THIS LINE IS REFERENCED IN ERROR MESSAGE print("leds[",j,"] = CRGB(",r, "," ,g, ",", b, ");") #print pixel colorchange to console del image Why do I get this error? To me, this seems really strange. I input 2 images and it works just fine. However when I have white pixels at a certain position in the image, I get

问题 I'm trying to get an Image's pixel RGB with the PIL Image Library. With this code, I ran into the error: for i in range(width): for j in range(height): r,g,b=(image.getpixel((i,j))) #THIS LINE IS REFERENCED IN ERROR MESSAGE print("leds[",j,"] = CRGB(",r, "," ,g, ",", b, ");") #print pixel colorchange to console del image Why do I get this error? To me, this seems really strange. I input 2 images and it works just fine. However when I have white pixels at a certain position in the image, I get

来源： https://stackoverflow.com/questions/32128095/python-too-many-values-to-unpack

问题 I want to store a list of datetimes in a binary file in Python. EDIT: by "binary" I mean the best digital representation for each datatype. The application for this is to save GPS trackpoints composed by (unix-timestamp, latitude, longitude, elevation), so the whole structure is little-endian "Long, float, float, float", with four bytes to each value. NOTE: I don't use "unix-timestamp" due to any affection to the Unix platform, but only as an unequivocal way to represent the value of a

问题 I want to store a list of datetimes in a binary file in Python. EDIT: by "binary" I mean the best digital representation for each datatype. The application for this is to save GPS trackpoints composed by (unix-timestamp, latitude, longitude, elevation), so the whole structure is little-endian "Long, float, float, float", with four bytes to each value. NOTE: I don't use "unix-timestamp" due to any affection to the Unix platform, but only as an unequivocal way to represent the value of a

问题 I want to store a list of datetimes in a binary file in Python. EDIT: by "binary" I mean the best digital representation for each datatype. The application for this is to save GPS trackpoints composed by (unix-timestamp, latitude, longitude, elevation), so the whole structure is little-endian "Long, float, float, float", with four bytes to each value. NOTE: I don't use "unix-timestamp" due to any affection to the Unix platform, but only as an unequivocal way to represent the value of a

问题 Okay, so I have searched for dll files that will allow me to unrar files and I was able to find quite a few such as unrar.dll, chilkat, sharpcompress and some more but I wanted to use the one provided by Rar themselves. So I referenced the DLL file in my project and imported it. I was using unrar.dll. But I wasn't able to find any up to date code to allow me to test and try things out. All the examples I found were either not up to date or not for Vb.net. I also tried the official example,

问题 Consider this short example: $a = pack("d",255); print length($a)."\n"; # Prints 8 $aa = pack("ddddd", 255,123,0,45,123); print length($aa)."\n"; # Prints 40 @unparray = unpack("d "x5, $aa); print scalar(@unparray)."\n"; # Prints 5 print length($unparray[0])."\n" # Prints 3 printf "%d\n", $unparray[0] ' # Prints 255 # As a one-liner: # perl -e '$a = pack("d",255); print length($a)."\n"; $aa = pack("dd", 255,123,0,45,123); print length($aa)."\n"; @unparray = unpack("d "x5, $aa); print scalar(