In this example, how do I write a Python script to accomplish this?

[CharlesBanks2]

In this example, how do I write a Python script to accomplish this result:

Site   ID

SIte A 0001

Site A 0001

SIte A 0001

Site A 0001

Site B 0002

SIte B 0002

Site B 0002

Site C 0003

SIte D 0004

[CharlesBanks2]

Yes, I did, and got something like this:

FIELD	NEED TO BE
xxx_ 9999TUNK10_	xxx_ 9999TUNK10_001
xxx_ 9999TUNK10_	xxx_ 9999TUNK10_002
xxx_ 9999TUNK10_	xxx_ 9999TUNK10_003
xxx_ 9999BANK12_	xxx_ 9999BANK12_002

[DanPatterson_Retired]

# lines 7... change to
        cnt += 0   # ---- try changing this
        ret = "{} {:04.0f}".format(val, cnt)
    else:
        cnt += 1   # ---- and this
        ret = "{} {:04.0f}".format(val, cnt)‍‍‍‍‍‍‍‍‍‍‍‍

[CharlesBanks2]

I got an error: 999999 : Error executing function.

999999 : Error executing function.

[DanPatterson_Retired]

show your field calculator dialog with the function and your expression filled in

Any of you other peeps want to leap in... lots of viewers... no suggestions from the gallery???  You can take over if you want

[RandyBurton]

Peeping in.....

A dictionary solution could look like something like this:

data = ['xxx_9999TUNK10_',
        'xxx_9999TUNK10_',
        'xxx_9999TUNK10_',
        'xxx_9999BANK12_',
        'xxx_9999BANK17_',
        'xxx_9999BANK1_',
        'xxx_9999BANK20_',
        'xxx_9999BANK20_',
        'xxx_9999BANK20_',
        'xxx_9999BANK30_' ]

d = {}
cnt = 0

for row in data:
    if row not in d.keys():
        cnt += 1
        d[row] = cnt
        print "{}{:04.0f}".format(row, cnt)
    else:
        print "{}{:04.0f}".format(row, d[row])

'''
Results:
xxx_9999TUNK10_0001
xxx_9999TUNK10_0001
xxx_9999TUNK10_0001
xxx_9999BANK12_0002
xxx_9999BANK17_0003
xxx_9999BANK1_0004
xxx_9999BANK20_0005
xxx_9999BANK20_0005
xxx_9999BANK20_0005
xxx_9999BANK30_0006
'''‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Is the prefixed 'xxx_' always the same, or does it vary?  If it varies, you will need to do some string splitting, etc.

Is the postfixed '_' always present?  If not, the formatting statement can be modified to include it.

By making the dictionary 'd' and the counter 'cnt' global, you should be able to make it work for the field calculator.  The code should also work with an update cursor, should you wish to go that route.

[CharlesBanks2]

Prefix is always the same and suffix is always present and varies. Could I

substitute the data portion with the field name?

Charles Banks

[RandyBurton]

Not sure I understand your question.  Would something like this do what you want?

data = ['xxx_9999TUNK10_',
        'xxx_9999TUNK10_',
        'xxx_9999TUNK10_',
        'xxx_9999BANK12_',
        'xxx_9999BANK17_',
        'xxx_9999BANK1_',
        'xxx_9999BANK20_',
        'xxx_9999BANK20_',
        'xxx_9999BANK20_',
        'xxx_9999BANK30_' ]


d = {} # empty dictionary
cnt = 0 # counter
def seq_count(fname, val):
    global d
    global cnt

    if val not in d.keys():
        cnt += 1
        d[val] = cnt
        return "{}_{}{:04.0f}".format(fname, val, cnt)
    else:
        return "{}_{}{:04.0f}".format(fname, val, d[val])


fieldName = 'myField'
for item in data:
    print seq_count(fieldName, item)

'''
Results:
myField_xxx_9999TUNK10_0001
myField_xxx_9999TUNK10_0001
myField_xxx_9999TUNK10_0001
myField_xxx_9999BANK12_0002
myField_xxx_9999BANK17_0003
myField_xxx_9999BANK1_0004
myField_xxx_9999BANK20_0005
myField_xxx_9999BANK20_0005
myField_xxx_9999BANK20_0005
myField_xxx_9999BANK30_0006
'''‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

[CharlesBanks2]

Yes.

Charles Banks

[CharlesBanks2]

Sorry about the delay. Here it is: