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I am trying to use the Dissolve_management tool using ArcPy. I keep getting an error that reads "Parameters are not valid.", and I cannot figure out where I am going wrong. Here is the code: 

env.workspace = "H:/Data/"
input = "Analysis/mtbs_state_2000/al.shp"
output = "Analysis/2000_dissolved/al.shp"
statistics_fields = [["km2", "SUM"], ["HU90", "SUM"]]
arcpy.Dissolve_management(input, output, "Fire_ID", statistics_fields)

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6
  • Try ["Fire_ID"] (with brackets) ?
    – Erica
    Commented Dec 5, 2015 at 22:36
  • Unfortunately, no luck :/
    – Anthony To
    Commented Dec 5, 2015 at 22:47
  • 2
    env.workspace shouldn't have a trailing slash.
    – Paul
    Commented Dec 5, 2015 at 22:56
  • Nice catch Paul. However, I'm still seeing the issue
    – Anthony To
    Commented Dec 6, 2015 at 0:21
  • Are those the actual field names or are they aliases?
    – Paul
    Commented Dec 6, 2015 at 5:10

1 Answer 1

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I think your Analysis folder is not being accessed, try: 

# also notice the double slashes throughout
env.workspace = "H:\\Data" 
input = env.workspace +"\\Analysis\\mtbs_state_2000\\al.shp"
output = env.workspace +"\\Analysis\\2000_dissolved\\al.shp"
statistics_fields = [["km2", "SUM"], ["HU90", "SUM"]]
arcpy.Dissolve_management(input, output, "Fire_ID", statistics_fields)
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6
  • This is assuming the 'Analysis' folder is in 'H:/Data'
    – yanes
    Commented Dec 5, 2015 at 23:24
  • 1
    os.path.join() is your friend. Though, it kind of defeats the purpose of setting env.workspace if you are just going to concatenate it anyways....
    – Paul
    Commented Dec 5, 2015 at 23:30
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    Are you sure that double forward slashes ("//") will not itself cause a problem? I know double backslashes is fine ("\\"), as well as single forward slash ("/") and lastly single backslashes ("\") but only with an r before the string.
    – PolyGeo ♦
    Commented Dec 6, 2015 at 0:10
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    Thanks for the answer Yang. The ArcPy documentation uses the single forward slash notation, and I've used that with all my other scripts without any issues. But I tried your notation, still not working
    – Anthony To
    Commented Dec 6, 2015 at 0:20
  • Sorry.. @PolyGeo is right it is either double back slash("\\") or a single forward slash ("/") with an r in front of the path. For example: `env.workspace = r"H:/Data". I've edited the answer to reflect this.
    – yanes
    Commented Dec 6, 2015 at 1:35

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