I am trying to remove prefixes from a field, eg. SV192W001 to 192W001. I run the following code and it runs without any errors but when I look at the field none of the prefixes are removed/replaced. Any help appreciated. Thanks in advance. import arcpy from arcpy import env # Set workspace arcpy . env . workspace = "B:/Projects/Duplicate Assets/Duplicate.gdb/dwSystemValve" fieldName = "ValveID" # Remove prefixes from ValveID print ( "Removing prefixes" ) fieldName . replace ( "SV" , "" ) fieldName . replace ( "HV" , "" ) fieldName . replace ( "SR" , "" ) print ( "Done" )

Oh, your new code makes it more clear to me what you are trying to do. Here are some expressions that should work. expression = '!ValveID!.replace("SV","").replace("HV","").replace("SR","").replace("ZB","")' # or simply remove the first two characters: expression = '!ValveID![2:]'

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Replace Stand Alone Script

GIS_geek

I am trying to remove prefixes from a field, eg. SV192W001 to 192W001. I run the following code and it runs without any errors but when I look at the field none of the prefixes are removed/replaced. Any help appreciated. Thanks in advance.

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">from</SPAN> arcpy <SPAN class="keyword token">import</SPAN> env

<SPAN class="comment token"># Set workspace</SPAN>
arcpy<SPAN class="punctuation token">.</SPAN>env<SPAN class="punctuation token">.</SPAN>workspace <SPAN class="operator token">=</SPAN> <SPAN class="string token">"B:/Projects/Duplicate Assets/Duplicate.gdb/dwSystemValve"</SPAN>

fieldName <SPAN class="operator token">=</SPAN> <SPAN class="string token">"ValveID"</SPAN>

<SPAN class="comment token"># Remove prefixes from ValveID</SPAN>
<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"Removing prefixes"</SPAN><SPAN class="punctuation token">)</SPAN>
fieldName<SPAN class="punctuation token">.</SPAN>replace<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"SV"</SPAN><SPAN class="punctuation token">,</SPAN><SPAN class="string token">""</SPAN><SPAN class="punctuation token">)</SPAN>
fieldName<SPAN class="punctuation token">.</SPAN>replace<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"HV"</SPAN><SPAN class="punctuation token">,</SPAN><SPAN class="string token">""</SPAN><SPAN class="punctuation token">)</SPAN>
fieldName<SPAN class="punctuation token">.</SPAN>replace<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"SR"</SPAN><SPAN class="punctuation token">,</SPAN><SPAN class="string token">""</SPAN><SPAN class="punctuation token">)</SPAN>

<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"Done"</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>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

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curtvprice

Oh, your new code makes it more clear to me what you are trying to do. Here are some expressions that should work.

expression <SPAN class="operator token">=</SPAN> <SPAN class="string token">'!ValveID!.replace("SV","").replace("HV","").replace("SR","").replace("ZB","")'</SPAN>
<SPAN class="comment token"># or simply remove the first two characters:</SPAN>
expression <SPAN class="operator token">=</SPAN> <SPAN class="string token">'!ValveID![2:]‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍'</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

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DanPatterson_Retired

inTable <SPAN class="operator token">=</SPAN> <SPAN class="string token">"dwValves_copy"</SPAN>
fieldName <SPAN class="operator token">=</SPAN> <SPAN class="string token">"ValveID"</SPAN>

code_block <SPAN class="operator token">=</SPAN> <SPAN class="string token">'''
def r(a):
    """replace the values in the field"""
    if a in ("SV", "HV", "SR", "ZB"):
        return a.replace(a, "")
    return a
'''</SPAN>

expression <SPAN class="operator token">=</SPAN> <SPAN class="string token">"r(!ValveID!)"</SPAN>
arcpy<SPAN class="punctuation token">.</SPAN>CalculateField_management<SPAN class="punctuation token">(</SPAN>inTable<SPAN class="punctuation token">,</SPAN> fieldName <SPAN class="punctuation token">,</SPAN> expression<SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"PYTHON3"</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>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

should you need to add more values to your list of things to replace, just add them to line 7

GIS_geek

Thank you all for your help!!

curtvprice

Oh, your new code makes it more clear to me what you are trying to do. Here are some expressions that should work.

expression <SPAN class="operator token">=</SPAN> <SPAN class="string token">'!ValveID!.replace("SV","").replace("HV","").replace("SR","").replace("ZB","")'</SPAN>
<SPAN class="comment token"># or simply remove the first two characters:</SPAN>
expression <SPAN class="operator token">=</SPAN> <SPAN class="string token">'!ValveID![2:]‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍'</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

DanPatterson_Retired

Hector, you would need a code block, in calculate field

<SPAN class="keyword token">def</SPAN> <SPAN class="token function">r</SPAN><SPAN class="punctuation token">(</SPAN>a<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
    <SPAN class="string token">"""replace the values in the field"""</SPAN>
    <SPAN class="keyword token">if</SPAN> a <SPAN class="keyword token">in</SPAN> <SPAN class="punctuation token">(</SPAN><SPAN class="string token">"SV"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"HV"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"SR"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"ZB"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
        <SPAN class="keyword token">return</SPAN> a<SPAN class="punctuation token">.</SPAN>replace<SPAN class="punctuation token">(</SPAN>a<SPAN class="punctuation token">,</SPAN> <SPAN class="string token">""</SPAN><SPAN class="punctuation token">)</SPAN>
    <SPAN class="keyword token">return</SPAN> a<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

your condition wasn't an 'and' but an 'or' since the row value can only be 1 thing

expression section

r(!YourField!)

GIS_geek

I did think using field calculator, but I have more to this script and additional feature classes. I did implement Calculate Field and it sort of worked. At the end of the process I looked at my data and only the "ZB" was removed from all values containing it in the ValveID field. Does the CalculateField_management tool only accept one statement in the expression or does it have the ability to accept multiple statements? I tried using '&' and ',' instead of 'and' and both returned errors. Here is my updated code. Still a newbie to python and trying to get a hang of it. Thanks for your help.

<SPAN class="keyword token">import</SPAN> arcpy
<SPAN class="keyword token">from</SPAN> arcpy <SPAN class="keyword token">import</SPAN> env

<SPAN class="comment token"># Set workspace</SPAN>
arcpy<SPAN class="punctuation token">.</SPAN>env<SPAN class="punctuation token">.</SPAN>workspace <SPAN class="operator token">=</SPAN> <SPAN class="string token">"B:/Projects/Duplicate Assets/Duplicate.gdb"</SPAN>

<SPAN class="comment token"># Set variables</SPAN>
inTable <SPAN class="operator token">=</SPAN> <SPAN class="string token">"dwValves_copy"</SPAN>
fieldName <SPAN class="operator token">=</SPAN> <SPAN class="string token">"ValveID"</SPAN>
expression <SPAN class="operator token">=</SPAN> <SPAN class="string token">'!ValveID!.replace("SV","")'</SPAN> <SPAN class="operator token">and</SPAN> <SPAN class="string token">'!ValveID!.replace("HV","")'</SPAN> 
<SPAN class="operator token">and</SPAN> <SPAN class="string token">'!ValveID!.replace("SR","")'</SPAN> <SPAN class="operator token">and</SPAN> <SPAN class="string token">'!ValveID!.replace("ZB","")'</SPAN>

<SPAN class="comment token"># Remove prefixes from ValveID</SPAN>
<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"Removing prefixes"</SPAN><SPAN class="punctuation token">)</SPAN>
arcpy<SPAN class="punctuation token">.</SPAN>CalculateField_management<SPAN class="punctuation token">(</SPAN>inTable<SPAN class="punctuation token">,</SPAN> fieldName <SPAN class="punctuation token">,</SPAN> expression<SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"PYTHON3"</SPAN><SPAN class="punctuation token">)</SPAN>

<SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"Done"</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>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

curtvprice

Normally field names cannot be changed but there is a geoprocessing tool for that: Alter Field (only supported in ArcGIS Pro). In ArcMap you need to create a new field, copy the data over using Calculate Field (as Dan suggests) and delete the old field once you have verified the data have been successfully copied.

I should warn you that field names starting with a number can cause you major problems down the road

https://community.esri.com/people/curtvprice/blog/2016/05/07/how-to-name-things-in-arcgis?sr=search&searchId=2e41b637-a244-44e9-84ad-8888868bbd37&searchIndex=0

DanPatterson_Retired

That script does nothing since the field is never acquired. It would probably just be faster to use the field calculator to accomplish what you need, however, if you need to do this within a script, then you have to implement

Calculate Field—Data Management toolbox | ArcGIS Desktop

unless you want to get involved with update cursors

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