How To Fill Nan Value With The Previous Available In The Row?

I need to fill the nan value in a dataframe by using the previous available value in a row, as the data are timeseries. Here there is an example: 1 2 3 4 b b nan c c na

Solution 1:

Use ffill along the first axis.

df.ffill(axis=1)12340  b  b  b  c1cc  d  d
2  d  d  d  c

Solution 2:

If you want to fill nan cells by value from row in up:

df.ffill(axis=0)