Hi, I want to loop the below process for multiple years so tested with one year. I am getting an error when it tries to change the (YEAR) as calculate field as a number variable with the corresponding year. Cannot understand what I am doing wrong here. Everything else up to line 29 is working. Problem is inside the code block section. Any help is greatly appreciated. Thanks in advance. ExecuteError : ERROR 000539 : Error running expression : getClass ( 1998.0 ) Traceback ( most recent call last ) : File " " , line 1 , in module > File " " , line 4 , in getClass NameError : global name 'yr' is not defined Failed to execute ( CalculateField ) . years = [ 1997 ] # Write the selected features to a new featureclass for year in years : arcpy . CopyFeatures_management ( "PLSS_KS_All_GCS" , r "C:/Users/Desktop/Flood/KS_All.gdb/PLSS_KS_All_WklyPrSum_PRISM_800m_" + str ( year ) + "_new" ) # Set environment settings arcpy . env . workspace = "H:/PRISM_800m_weekly_sum_tif" # Set local variables inPointFeatures = r "C:/Users/Desktop/Flood/KS_All.gdb/PLSS_KS_All_WklyPrSum_PRISM_800m_" + str ( year ) + "_new.shp" # Set local variables inRasterList = [ [ "Week_1_Sum" + str ( year ) + "_10.tif" , "Oct_PCPwk1" ] , [ "Week_2_Sum" + str ( year ) + "_10.tif" , "Oct_PCPwk2" ] , [ "Week_3_Sum" + str ( year ) + "_10.tif" , "Oct_PCPwk3" ] , [ "Week_4_Sum" + str ( year ) + "_10.tif" , "Oct_PCPwk4" ] , [ "Week_5_Sum" + str ( year ) + "_10.tif" , "Oct_PCPwk5" ] , [ "Week_1_Sum" + str ( year ) + "_11.tif" , "Nov_PCPwk1" ] , [ "Week_2_Sum" + str ( year ) + "_11.tif" , "Nov_PCPwk2" ] ] # Check out the ArcGIS Spatial Analyst extension license arcpy . CheckOutExtension ( "Spatial" ) # Execute ExtractValuesToPoints ExtractMultiValuesToPoints ( inPointFeatures , inRasterList , "BILINEAR" ) #NONE fieldName = "YEAR" expression = "getClass(!YEAR!)" codeblock = """def getClass(YEAR): global yr yr=1997 if YEAR >= 1998: return yr else: return -9999""" # Execute AddField #arcpy.AddField_management(inTable, fieldName, "SHORT") # Execute CalculateField arcpy . CalculateField_management ( inPointFeatures , fieldName , expression , "PYTHON_9.3" , codeblock )

You could do this with a cursor instead of field calculator: # Define search cursor urows = arcpy . da . UpdateCursor ( inPointFeatures , "YEAR" ) # Loop through each row in cursor for urow in urows : # If the value for YEAR is greater than or equal to 1998 yr is 1997 if urow [ 0 ] >= 1998 : yr = 1997 # If not yr is -9999 else : yr = - 9999 # Update the YEAR attribute for this row urow [ 0 ] = yr urows . updateRow ( urow ) # yr variable is available outside for loop print yr UpdateCursor—Help | ArcGIS for Desktop

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Passing a number variable as global in python

DuminduJayasekera

Hi,

I want to loop the below process for multiple years so tested with one year. I am getting an error when it tries to change the (YEAR) as calculate field as a number variable with the corresponding year. Cannot understand what I am doing wrong here. Everything else up to line 29 is working. Problem is inside the code block section.

Any help is greatly appreciated.

Thanks in advance.

ExecuteError<SPAN class="punctuation token">:</SPAN> ERROR <SPAN class="number token">000539</SPAN><SPAN class="punctuation token">:</SPAN> Error running expression<SPAN class="punctuation token">:</SPAN> getClass<SPAN class="punctuation token">(</SPAN><SPAN class="number token">1998.0</SPAN><SPAN class="punctuation token">)</SPAN> 
Traceback <SPAN class="punctuation token">(</SPAN>most recent call last<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp; File <SPAN class="string token">"<expression>"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> <SPAN class="operator token"><</SPAN>module<SPAN class="operator token">></SPAN>
&nbsp; File <SPAN class="string token">"<string>"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">4</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> getClass
NameError<SPAN class="punctuation token">:</SPAN> <SPAN class="keyword token">global</SPAN> name <SPAN class="string token">'yr'</SPAN> <SPAN class="keyword token">is</SPAN> <SPAN class="operator token">not</SPAN> defined

Failed to execute <SPAN class="punctuation token">(</SPAN>CalculateField<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN>
‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

years <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="number token">1997</SPAN><SPAN class="punctuation token">]</SPAN> 
<SPAN class="comment token"># Write the selected features to a new featureclass</SPAN>
<SPAN class="keyword token">for</SPAN> year <SPAN class="keyword token">in</SPAN> years<SPAN class="punctuation token">:</SPAN>
 arcpy<SPAN class="punctuation token">.</SPAN>CopyFeatures_management<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"PLSS_KS_All_GCS"</SPAN><SPAN class="punctuation token">,</SPAN> r<SPAN class="string token">"C:/Users/Desktop/Flood/KS_All.gdb/PLSS_KS_All_WklyPrSum_PRISM_800m_"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_new"</SPAN><SPAN class="punctuation token">)</SPAN>

 <SPAN class="comment token"># Set environment settings</SPAN>
&nbsp; arcpy<SPAN class="punctuation token">.</SPAN>env<SPAN class="punctuation token">.</SPAN>workspace <SPAN class="operator token">=</SPAN> <SPAN class="string token">"H:/PRISM_800m_weekly_sum_tif"</SPAN> 
 
<SPAN class="comment token"># Set local variables</SPAN>
 inPointFeatures <SPAN class="operator token">=</SPAN> r<SPAN class="string token">"C:/Users/Desktop/Flood/KS_All.gdb/PLSS_KS_All_WklyPrSum_PRISM_800m_"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_new.shp"</SPAN>

 
<SPAN class="comment token"># Set local variables</SPAN>
 inRasterList <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Week_1_Sum"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_10.tif"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"Oct_PCPwk1"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> 
 <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Week_2_Sum"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_10.tif"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"Oct_PCPwk2"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN> 
 <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Week_3_Sum"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_10.tif"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"Oct_PCPwk3"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Week_4_Sum"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_10.tif"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"Oct_PCPwk4"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Week_5_Sum"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_10.tif"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"Oct_PCPwk5"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Week_1_Sum"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_11.tif"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"Nov_PCPwk1"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Week_2_Sum"</SPAN> <SPAN class="operator token">+</SPAN> str<SPAN class="punctuation token">(</SPAN>year<SPAN class="punctuation token">)</SPAN><SPAN class="operator token">+</SPAN> <SPAN class="string token">"_11.tif"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"Nov_PCPwk2"</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">]</SPAN>
&nbsp; 
 
 <SPAN class="comment token"># Check out the ArcGIS Spatial Analyst extension license</SPAN>
 arcpy<SPAN class="punctuation token">.</SPAN>CheckOutExtension<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"Spatial"</SPAN><SPAN class="punctuation token">)</SPAN>

<SPAN class="comment token"># Execute ExtractValuesToPoints </SPAN>
 ExtractMultiValuesToPoints<SPAN class="punctuation token">(</SPAN>inPointFeatures<SPAN class="punctuation token">,</SPAN> inRasterList<SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"BILINEAR"</SPAN><SPAN class="punctuation token">)</SPAN> <SPAN class="comment token">#NONE</SPAN>
 
 
 fieldName <SPAN class="operator token">=</SPAN> <SPAN class="string token">"YEAR"</SPAN>
 expression <SPAN class="operator token">=</SPAN> <SPAN class="string token">"getClass(!YEAR!)"</SPAN>
 codeblock <SPAN class="operator token">=</SPAN> <SPAN class="string token">"""def getClass(YEAR):
 global yr
 yr=1997
 if YEAR >= 1998:
 return yr
 else:
 return -9999"""</SPAN>
 
 <SPAN class="comment token"># Execute AddField</SPAN>
 <SPAN class="comment token">#arcpy.AddField_management(inTable, fieldName, "SHORT")</SPAN>
 
 <SPAN class="comment token"># Execute CalculateField </SPAN>
 arcpy<SPAN class="punctuation token">.</SPAN>CalculateField_management<SPAN class="punctuation token">(</SPAN>inPointFeatures<SPAN class="punctuation token">,</SPAN> fieldName<SPAN class="punctuation token">,</SPAN> expression<SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"PYTHON_9.3"</SPAN><SPAN class="punctuation token">,</SPAN> codeblock<SPAN class="punctuation token">)</SPAN>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

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DuminduJayasekera

@Randy. Thanks it worked.

RandyBurton

As Dan Patterson‌ mentioned, some of you issues may be with formatting. The indentation is not very clear from the code posted.

In line 41 you are creating a new field "YEAR", and in line 44 you are using the codeblock to populate that new field. Since the new field is set to null, the codeblock section probably isn't doing a valid comparison. I would suggest removing the codeblock and replacing the expression with the year.

year <SPAN class="operator token">=</SPAN> <SPAN class="number token">1997</SPAN> <SPAN class="comment token"># this is essentially year from the loop</SPAN>

<SPAN class="comment token"># Execute CalculateField </SPAN>
arcpy<SPAN class="punctuation token">.</SPAN>CalculateField_management<SPAN class="punctuation token">(</SPAN>inPointFeatures<SPAN class="punctuation token">,</SPAN> fieldName<SPAN class="punctuation token">,</SPAN> year<SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"PYTHON_9.3"</SPAN><SPAN class="punctuation token">,</SPAN> "<SPAN class="comment token">#")</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

You could do this with a cursor instead of field calculator:

<SPAN class="comment token"># Define search cursor</SPAN>
urows <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>da<SPAN class="punctuation token">.</SPAN>UpdateCursor<SPAN class="punctuation token">(</SPAN>inPointFeatures<SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"YEAR"</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="comment token"># Loop through each row in cursor</SPAN>
<SPAN class="keyword token">for</SPAN> urow <SPAN class="keyword token">in</SPAN> urows<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># If the value for YEAR is greater than or equal to 1998 yr is 1997</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">if</SPAN> urow<SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">>=</SPAN> <SPAN class="number token">1998</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; yr <SPAN class="operator token">=</SPAN> <SPAN class="number token">1997</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># If not yr is -9999</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">else</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; yr <SPAN class="operator token">=</SPAN> <SPAN class="operator token">-</SPAN><SPAN class="number token">9999</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="comment token"># Update the YEAR attribute for this row</SPAN>
&nbsp;&nbsp;&nbsp; urow<SPAN class="punctuation token">[</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> yr
&nbsp;&nbsp;&nbsp; urows<SPAN class="punctuation token">.</SPAN>updateRow<SPAN class="punctuation token">(</SPAN>urow<SPAN class="punctuation token">)</SPAN>
<SPAN class="comment token"># yr variable is available outside for loop</SPAN>
<SPAN class="keyword token">print</SPAN> yr‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

UpdateCursor—Help | ArcGIS for Desktop

DuminduJayasekera

OK. I updated the code inside the code block manually to reflect what you suggested and it worked. (Please see the revised code above). But, I need to pass the value in "year" in the main script into the code block. For example in this case 1997. I need to avoid manually enter the year into the code block so I can run the script for multiple years. How can I achieve that?

DarrenWiens2

I think you need to initialize yr inside the codeblock string. The variables inside the codeblock don't communicate with those in the main script.

DuminduJayasekera

Thanks Dan for the reply. I did as you suggested but still getting the same error. Please see the revised error message and code above.

DanPatterson_Retired

in your code block, try putting

yr = -9999

on a new line before the def line

you have to initialize yr before you can make it global

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