Field calculator to copy numeric values from other fields

Question

FieldA contains text: both numeric(123) and alpha-numeric(123a, 2-3, 3/2, '). FieldB is longstring. I want to use field calculator and codeblock on FieldB to bring from Field A only the numeric values.

while True:

try:
    val = int(x)
    print (val)
    break
except ValueError:
    print ("non-numeric")
    break

I tried something similar to the code seen here, but the process fails at some point. I just need something to see if fieldA .isdigit and if true copy to fieldB(if false pass a string "non-numeric"). Or anything similar.

I am using ArcGIS 10.2 for Desktop.

Answer 1

Have a look at this bit of code as your fieldB is of type string it does not need to do any type conversion.

This bit of python goes in the code block:

def numonly(s):
  if s.isdigit():
    return s
  else:
    return ""

Answer 2

Open Field Calculator on FieldB. On Field Calculator, check Show Codeblock.

Paste this code under Pre-Logic Script Code:

# assuming FieldB is Long Integer as you mentioned "FieldB is longstring".
# there is no such data type. I'm taking "longstring" as typo error for Long Integer

def get_numbers(value):
    return value if str(value).strip().isdigit() else None

---

# assuming FieldB is Text (String) as you mentioned "FieldB is longstring".
# there is no such data type. I'm taking "longstring" as typo error for Long Integer

def get_numbers(value):
    return value if str(value).strip().isdigit() else None

and call this function for FieldB.

FieldB=
get_numbers(!FieldA!)

I hope this will help. :)