Dear R users,

I am reading data from a file where there are some missing that are
represented by -9999.00.
I am using the command below.
=====My original data ===========

PARM = TMPC;T12X;T12N;DWPC;PALT;SKNT;DRCT;P24M;CLCL


    STN    YYMMDD/HHMM      TMPC     T12X     T12N     DWPC     PALT
SKNT
                            DRCT     P24M     CLCL
 820420    110429/1200     22.50 -9999.00    22.40    22.20 -9999.00
0.00
                            0.00    84.00     4.00
 820980    110429/1200     26.90 -9999.00    23.40    24.10  1010.20
2.91
                          360.00     2.00     6.00
 821130    110429/1200     24.30 -9999.00    23.30    23.70 -9999.00
1.94
                          230.00     3.00     4.00
 821410    110429/1200     24.40 -9999.00    23.70    24.20  1011.80
2.91
===========

dados<-read.table("2011042912_teste.dat",sep='',fill=TRUE,na.strings="-9999.00",skip=4)
head(dados)
      V1          V2   V3 V4   V5   V6     V7   V8 group
1 820420 110429/1200 22.5 NA 22.4 22.2     NA 0.00     1
2      0       84.00  4.0 NA   NA   NA     NA   NA     1
3 820980 110429/1200 26.9 NA 23.4 24.1 1010.2 2.91     2
4    360        2.00  6.0 NA   NA   NA     NA   NA     2
5 821130 110429/1200 24.3 NA 23.3 23.7     NA 1.94     3
6    230        3.00  4.0 NA   NA   NA     NA   NA     3
=============
After some procedures a have the data as below:
> head(Alldados)


  Station_NO       date1 T_2M TMAX_2M TMIN_2M TD_2M     PS FF_10M DD_10M
1     820420 110429/1200 22.5      NA    22.4  22.2     NA   0.00      0
2     820980 110429/1200 26.9      NA    23.4  24.1 1010.2   2.91    360
3     821130 110429/1200 24.3      NA    23.3  23.7     NA   1.94    230
4     821410 110429/1200 24.4      NA    23.7  24.2 1011.8   2.91    270
5     821450 110429/1200 28.2      NA    21.1  25.8 1008.8   0.00      0
6     821810 110429/1200 23.3      NA    22.8  22.9 1001.6   0.00      0
  TOT_PRCP CLCL      date2
1    84.00   NA 2011042912
2     2.00   NA 2011042912
3     3.00   NA 2011042912
4    12.00   NA 2011042912
5     6.00   NA 2011042912
6    38.00   NA 2011042912

But  I need to feed my database. These missings should be represented by
NULL.
I mean, all "NA" should be replaced by "NULL" in my database.
I am trying the command below to pick up the rows and columns with NA but I
don't know how to fill the original data :

which(is.na(Alldados),arr.ind=TRUE)

But I don't know how to replace each NA with NULL. I tried using as.null but
NA is not replace at all.

I hope someone could help me.

Best Wishes,
Nilza Barros

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