Syntax error: keyword can't be an expression with the function "Con"?

Question

From How can I reclassify an integer raster to a float raster?, I would like to reclassify an integer raster "cpraster3.tif" to a float raster. For example, I would like to reclassify "Value" = 1 into 0.27, "Value" = 2 into 1.00 ...

Here is my code:

test_reclass = Float(Con(("cpraster3.tif", "Value" = 1, 0.27, Con("cpraster3.tif", "Value" = 2, 1.00, Con("cpraster3.tif", "Value" = 3, 2.9, Con("cpraster3.tif", "Value" = 4, 2.94, Con("cpraster3.tif", "Value" = 5, 5.37, Con("cpraster3.tif", "Value" = 6, 10.35, Con("cpraster3.tif", "Value" = 7, 16.49, Con("cpraster3.tif","Value" = 7, 22.08, 0.0)))))))))

But I have this error message:

Failed to run script - syntax error - keyword can't be an expression

Answer 1

Use == which is the equality operator, not a single = which is the assignment operator (i.e a = 1 assigns the value 1 to the variable a). You can also shorten your expression by having the comparison as the first argument and dropping the Value field.

E.g:

test_reclass = Float(Con("cpraster3.tif" == 1, 0.27, Con("cpraster3.tif" == 2, 1.00, Con("cpraster3.tif == 3, 2.9, Con("cpraster3.tif" == 4, etc...

All those nested Con functions are quite unwieldy though. Have you considered using the Reclassify function instead?