topic Re: Python lower string? in Python Questions

Python lower string?

JohannesBierer — Wed, 22 Oct 2014 12:16:20 GMT

After insert lower() there's nothing written in the field? What's wrong?

# Process: Feld berechnen
arcpy.CalculateField_management(FeldHinzugefuegt, "Pfad", "\"U:\\rips\\images\\tk50\\tk\" & ([BLATT_NR].lower()) & \"co\" & \"*.*\"", "VB", "")

Re: Python lower string?

Zeke — Wed, 22 Oct 2014 12:47:59 GMT

I'd put the calculation expression in a variable and check that. It kind of looks like your quotation marks are off, but honestly it's a bit hard to follow all that.

Re: Python lower string?

JohannesBierer — Wed, 22 Oct 2014 13:08:15 GMT

Thanks for the answer. The field calculation work without lower() function, so don't care about all the funny text around.

This must be the problem. Or can`t you lower the expression of a field string in this manner?

Re: Python lower string?

JamesCrandall — Wed, 22 Oct 2014 13:51:09 GMT

I don't believe ".lower()" can be used with the VB parser. That is Python.

Re: Python lower string?

JamesCrandall — Wed, 22 Oct 2014 13:53:32 GMT

Untested:

Likely what will work:

arcpy.CalculateField_management(FeldHinzugefuegt, "Pfad", r"U:\rips\images\tk50\tk\\" + ([BLATT_NR].lower()) + "co\\" + "*.*", "PYTHON_9.3", "")

Or from your original code:

arcpy.CalculateField_management(FeldHinzugefuegt, "Pfad", "\"U:\\rips\\images\\tk50\\tk\" + ([BLATT_NR].lower()) + \"co\" + \"*.*\"", "PYTHON_9.3", "")

Re: Python lower string?

DanPatterson_Retired — Wed, 22 Oct 2014 14:48:52 GMT

do it manually first then copy the syntax from the field calculator expression, fields in python are enclosed in ! ! marks, if that makes a difference

Re: Python lower string?

curtvprice — Thu, 23 Oct 2014 02:50:32 GMT

The VBScript function is LCase, as in

LCase("STRING")

I really like splitting long Python statements on multiple lines; the interpreter ignores the newline if you are inside ( 😞

# VB Parser
arcpy.CalculateField_management(FeldHinzugefuegt, "Pfad",  
    ("\"U:\\rips\\images\\tk50\\tk\" & LCASE([BLATT_NR])"
     "& \"co\" &  \"*.*\"", 
    "VB")'

# Python Parser (better, and will run in arcpy 64)!
arcpy.CalculateField_management(FeldHinzugefuegt, "Pfad",  
    ("\"U:\\rips\\images\\tk50\\tk" 
    "{}\\co\\*.*\".format(!BLATT_NR!).lower()"),
    "PYTHON")

Re: Python lower string?

JohannesBierer — Thu, 23 Oct 2014 07:32:40 GMT

Thanks for your answers, but I can't follow them or they don't work.

I try now to get a model to work and then export to python.

!BLATT_NR!.lower()

This works in the model

"U:\\rips\\images\\tk50\\" & !BLATT_NR!.lower() & "co.*"

For this I get a error message?

ERROR 000539: Error running expression: "U:\\rips\\images\\tk50\\" & "L6518".lower() & "co.*"

Traceback (most recent call last):

File "<expression>", line 1, in <module>

TypeError: unsupported operand type(s) for &: 'str' and 'str'

What's the problem?

Re: Python lower string?

JohannesBierer — Thu, 23 Oct 2014 07:34:07 GMT

What I need:

"U:\\rips\\images\\tk50\\l6518co.*"

Re: Python lower string?

JohannesBierer — Thu, 23 Oct 2014 08:09:34 GMT

This is for the model ok:

"U:\\rips\\images\\tk50\\" + !BLATT_NR!.lower() + "co*.*"

Result export to python:

# Process: Feld berechnen

arcpy.CalculateField_management(Orthos_Nummern_Layer, "Pfad", "\"U:\\\\rips\\\\images\\\\tk50\\\\\"

+ !BLATT_NR!.lower() + \"co*.* \"", "PYTHON", "")

No field calculate?

Tried this:

arcpy.CalculateField_management(Orthos_Nummern_Layer, "Pfad", "\"U:\\rips\\images\\tk50\\\" 
+ !BLATT_NR!.lower() + \"co*.* \"", "PYTHON", "")

No field calculate?

Re: Python lower string?

JohannesBierer — Thu, 23 Oct 2014 09:55:35 GMT

Python is to strange for me.

VB goes through - thanks Curtis ...

Re: Python lower string?

curtvprice — Thu, 23 Oct 2014 20:20:25 GMT

Your string is pretty complicated. You have it working in VB, great. If you decide you need to make it work in Python, I suggest dinking around at the Python command prompt. Turns out I did it wrong, see my trial and error here. I fixed the string in my post above - so nice you can edit your posts here!

# what I originally posted, wrong 
>>> "\'U:\\rips\\images\\tk50\\tk\'" "\'{}\\co\\*.*\'.format(!BLATT_NR!).lower()"
"'U:\\rips\\images\\tk50\\tk''{}\\co\\*.*'.format(!BLATT_NR!).lower()"
# try again
# Note the python must evaluate to a string expression
# for the CalculateField tool
>>> ("\"U:\\rips\\images\\tk50\\tk"
...  "{}\\co\\*.*\".format(!BLATT_NR!).lower()")
'"U:\\rips\\images\\tk50\\tk{}\\co\\*.*".format(!BLATT_NR!).lower()'