OpenRefine: Fill down with increasing counter - autofill

Question

Is it possible in OpenRefine to fill down blank cells with a counter instead of copying the top non-blank value?
In this example image:
Or here the same example as typed text - image this as a column from top to bottom:
1
1
blank
1
blank
blank
blank
blank
blank
1
I would like to see the column filled as follows (again, imagine top to bottom):
1
1
2
1
2
3
4
5
6
1
Thanks, help is very much appreciated.

Answer 1

It's not really simple. You have to:
1 Replace the blanks with something else, such as an "x"
2 Create a unique record for the entire dataset
3 Use this Jython script:
import itertools
data = row['record']['cells']['YOUR COLUMN NAME']['value']
x = itertools.count(2)
liste = []
for i, el in enumerate(data):
if data[i] == "x":
liste.append(x.next())
else:
x = itertools.count(2)
liste.append(el)
return ",".join([str(x) for x in liste])
4 Use Blank down to clear duplicates
5 Split the first multivalued cell.
Here is a screencast of the operations described above.
If you know a little Python, you can also transform your file using pandas. I do not know what is the most elegant way to do it, but this script should work.
import itertools
import pandas as pd
x = itertools.count(2)
def set_x():
global x
x = itertools.count(2)
set_x()
def increase(value):
if not value:
return next(x)
else:
set_x()
return value
data = pd.read_csv("your_file.csv", na_values=['nan'], keep_default_na=False)
data['column 1'] = data['column 1'].apply(lambda row: increase(row))
print(data)
data.to_csv("final_file.csv")

Answer 2

Here are two simple solutions using GREL.
Use records
You could move the column to the beginning, telling OpenRefine to use the numbers as records. You might need to transform the column to text to really convince OpenRefine to use it as records.
Then either add a new column or transform the existing one with the following expression.
1 + row.index - row.record.fromRowIndex
Use record markers
In case you don't want to use records or don't have a static number, you can create a similar setup. Imagine you have an incomplete counter like in the following table and want to fill it.
Origin
Desired
1
1
2
1
1
2
2
3
1
1
To fill the missing cells first add a new column based on your orignal column using the following expression and name it record_row_index.
if(isNonBlank(value), row.index, "")
After that fill down the original column and the new column record_row_index.
Then create a new column based on the original filled column using the following expression.
value + row.index - cells["record_row_index"].value
Hint: the expression is expecting both columns to be of type number.
If one of them is of type text, you can either transform the column beforehand or use toNumber() in the expression.
The following table shows how these operations are working together.
Origin
Origin filled
row.index
record_row_index
Desired
1
1
0
0
1 + 0 - 0 = 1
1
1
0
1 + 1 - 0 = 2
1
1
2
2
1 + 2 - 2 = 1
2
2
3
3
2 + 3 - 3 = 2
2
4
3
2 + 4 - 3 = 3
1
1
5
5
1 + 5 - 5 = 1