Tag Archives: dictionary

C++ enum to Python namedtuple (cont.)

Posted by Wujie of Dasheshire on

Here is a way to convert a C++ enum with values to Python.
C++ code:

typedef enum
{
   LADYBUG_RAW_CAM0           = ( 0x1 << 0 ),
   LADYBUG_RAW_CAM1           = ( 0x1 << 1 ),
   LADYBUG_RAW_CAM2           = ( 0x1 << 2 ),
   LADYBUG_RAW_CAM3           = ( 0x1 << 3 ),
   LADYBUG_RAW_CAM4           = ( 0x1 << 4 ),
   LADYBUG_RAW_CAM5           = ( 0x1 << 5 ),
   LADYBUG_ALL_RAW_IMAGES     =  0x0000003F,

   ...

   LADYBUG_PANORAMIC          = ( 0x1 << 12 ),

   LADYBUG_DOME               = ( 0x1 << 13 ),

   LADYBUG_SPHERICAL          = ( 0x1 << 14 ),

   LADYBUG_ALL_CAMERAS_VIEW   = ( 0x1 << 15 ),

   LADYBUG_ALL_OUTPUT_IMAGE   = 0x7FFFFFFF,

} LadybugOutputImage

The Python version:

LadybugOutputImage = dict(
   LADYBUG_RAW_CAM0           = ( 0x1 << 0 ),
   LADYBUG_RAW_CAM1           = ( 0x1 << 1 ),
   LADYBUG_RAW_CAM2           = ( 0x1 << 2 ),
   LADYBUG_RAW_CAM3           = ( 0x1 << 3 ),
   LADYBUG_RAW_CAM4           = ( 0x1 << 4 ),
   LADYBUG_RAW_CAM5           = ( 0x1 << 5 ),
   LADYBUG_ALL_RAW_IMAGES     =  0x0000003F,

   ...

   LADYBUG_PANORAMIC          = ( 0x1 << 12 ),

   LADYBUG_DOME               = ( 0x1 << 13 ),

   LADYBUG_SPHERICAL          = ( 0x1 << 14 ),

   LADYBUG_ALL_CAMERAS_VIEW   = ( 0x1 << 15 ),

   LADYBUG_ALL_OUTPUT_IMAGE   = 0x7FFFFFFF  )
LadybugOutputImage = namedtuple('Enum',
                       LadybugOutputImage.keys() )(**LadybugOutputImage)

Or even better, just get rid of all the packaging and commas on this type if it’s not too long and you have the patience. But you will also have to correct the indenting. Maybe there is a program out there that can do this editing for you.

   LADYBUG_RAW_CAM0           = ( 0x1 << 0 )
   LADYBUG_RAW_CAM1           = ( 0x1 << 1 )
   LADYBUG_RAW_CAM2           = ( 0x1 << 2 )
   LADYBUG_RAW_CAM3           = ( 0x1 << 3 )
   ...
   LADYBUG_ALL_CAMERAS_VIEW   = ( 0x1 << 15 )
   LADYBUG_ALL_OUTPUT_IMAGE   = 0x7FFFFFFF

tidbits from reading

Posted by Wujie of Dasheshire on

.index() vs. where()

.index() is the builtin function for finding the index of something in a list or tuple. This does not work with NumPy arrays! NP arrays rely on where() to return an array of indices that match the condition.

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for-else statement

‘else’ can be used after a for-loop. But here, the ‘else’ statement only executes if the for-loop completes all iterations. Think of it as using the for-loop to search for something, or expecting a break from the loop. If nothing is resolved or no break occurs then the else statement can be used for notification. The else can be used after a try-except in a similar way; executing only when nothing breaks down, throwing an exception.

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how to prevent a new-line character in a print() statement

Use a comma at the end. You can have consecutive print() statements print to the same line simply by adding a comma at the end of each line.

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Use a dictionary for formatting a long output string

%20s will format a string in the list after a text. But when using this formatting method, the order must match in the supplied list. %(keyword)20s or %(keyword)10f with a supplied dictionary can avoid the ordering issue and having to have the same variable or value in a list multiple times.

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use an asterisk * in front of a functions input argument to accept an infinite number of args.

def MyFunction( *args ): This will accept any number of arguments and create a list to use within the function.

—————————
ternary operation or inline if (iif)

In Java you can use a iif like this ( x == 2 ? y = 4 : y = 0 ).
( condition ? if true do this : if false do this)
I found that Python also has a version of this but ordered differently:
(do this) if (condition) else (do this if false)
Not the same order as java but still pretty straight forward.