bfill
Syntax
bfill(obj, [limit])
Arguments
obj is a vector/matrix/table.
limit is a positive integer.
Details
If obj is a vector: back fill the NULL values in obj with the next non-NULL value.
If obj is a matrix or a table: back fill the NULL values in each column of obj with the next non-NULL value.
Use the optional parameter limit to limit the number of NULL values to back fill for each block of NULL values.
This operation creates a new object and does not change the input obj. Function bfill! changes the input obj.
Examples
$ x=1 2 3 NULL NULL NULL 4 5 6
$ x.bfill();
[1,2,3,4,4,4,4,5,6]
$ x=1 2 3 NULL NULL NULL 4 5 6
$ x.bfill(1);
[1,2,3,,,4,4,5,6]
$ x.bfill!(2);
$ x;
[1,2,3,,4,4,4,5,6]
$ date=[2012.06.12,2012.06.12,2012.06.13,2012.06.14,2012.06.15]
$ sym=["IBM","MSFT","IBM","MSFT","MSFT"]
$ price=[,,26.56,,50.76]
$ qty=[,,4500,5600,6800]
$ timestamp=[09:34:07,09:35:26,09:36:42,09:36:51,09:36:59]
$ t=table(date,timestamp,sym,price,qty)
$ t;
date |
timestamp |
sym |
price |
qty |
|---|---|---|---|---|
2012.06.12 |
09:34:07 |
IBM |
||
2012.06.12 |
09:35:26 |
MSFT |
||
2012.06.13 |
09:36:42 |
IBM |
26.56 |
4500 |
2012.06.14 |
09:36:51 |
MSFT |
5600 |
|
2012.06.15 |
09:36:59 |
MSFT |
50.76 |
6800 |
$ t.bfill()
date |
timestamp |
sym |
price |
qty |
|---|---|---|---|---|
2012.06.12 |
09:34:07 |
IBM |
26.56 |
4500 |
2012.06.12 |
09:35:26 |
MSFT |
26.56 |
4500 |
2012.06.13 |
09:36:42 |
IBM |
26.56 |
4500 |
2012.06.14 |
09:36:51 |
MSFT |
50.76 |
5600 |
2012.06.15 |
09:36:59 |
MSFT |
50.76 |
6800 |
select date, timestamp, sym, price.bfill() as price, qty.bfill() as qty from t context by sym;
date |
timestamp |
sym |
price |
qty |
|---|---|---|---|---|
2012.06.12 |
09:34:07 |
IBM |
26.56 |
4500 |
2012.06.13 |
09:36:42 |
IBM |
26.56 |
4500 |
2012.06.12 |
09:35:26 |
MSFT |
50.76 |
5600 |
2012.06.14 |
09:36:51 |
MSFT |
50.76 |
5600 |
2012.06.15 |
09:36:59 |
MSFT |
50.76 |
6800 |