Dear R-Family,
I have a data-set of the following format. I am only presenting a part of it.
Date                A                 B                           C                                   D

 
 
 
 
 
 
  1-Jan-61
  0.00
  1.27
  8.128
  
  0.25
 
 
  
2-Jan-61
  
6.10
  
9.144
  
94.742
  
  

15.49


 
 
  3-Jan-61
  0.00
  0.508
  1.27
  
  
0.00


 
 
  4-Jan-61
  0.00
  0
  NA
  
  
0.00


 
 
  5-Jan-61
  0.00
  0
  0
  
  
0.00


 
 
  6-Jan-61
  0.00
  NA
  0
  
  
0.00


 
 
  7-Jan-61
  0.00
  0
  0
  
  
0.00


 
 
  8-Jan-61
  0.00
  NA
  0
  
  
0.00


 
 
  9-Jan-61
  0.00
  NA
  0
  
  
NA


 
 
  
10-Jan-61
  
0.00
  
4.064
  
4.826
  


  
0.76
 
You can see that each column has some NAs in it, What i want to do is to learn that which date has NA for each column. 
Here it should be something like the following

A                             B                                C                                        D
                       6-Jan-61                           4-Jan-61                         9-Jan-61
                       8-Jan-61
                       9-Jan-61

Thankyou very much in advance

Eliza 		 	   		  
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