[R] "Invalid object" error in boxplot

[Erik Iverson]

The advice is to store numeric data as numeric, and not factors.  Try 
str(yourdata) and you'll probably see that Diatoms is stored as a 
'factor'.  Are those commas used as decimal points?  read.table can deal 
with that if so.  If not, you do not need them, and should convert those 
fields to numeric after getting rid of the ',' characters.




mm745 at st-andrews.ac.uk wrote:
> Hi,
> 
> I'm trying to make a boxplot with the data at the end of the message, and when I
> try to execute the command
> 
>> boxplot(Diatoms) (or for any other field instead of "Diatoms")
> 
> I get the following error message:
> 
> Error in oldClass(stats) <- cl : adding class "factor" to an invalid object
> 
> Any advice would be much appreciated.
> 
> Thanks a lot,
> 
> Miriam
> 
> 
> 
>          Date Depth Diatoms  Bacteria         V1      V2      V3
> 1  15/02/2000     0      17   700,000 14,067,895 380,000  69,000
> 2  15/02/2000     2      17   316,680  9,311,160 250,000  26,000
> 3  15/02/2000    10      20   313,010  8,422,355 460,000  30,000
> 4  15/02/2000    20      21   374,535  9,259,900 280,000  33,000
> 5  22/02/2000     0      21   370,000 16,952,360 320,000  72,000
> 6  22/02/2000     2      21   462,480 10,526,390 360,000  64,000
> 7  22/02/2000    10      39   374,860  8,378,655 290,000  49,000
> 8  22/02/2000    20     140   381,900  9,468,550 390,000  73,000
> 9  29/02/2000     0     240   200,000  5,783,980 440,000  61,000
> 10 29/02/2000     2     240   224,125  8,077,105 600,000  89,000
> 11 29/02/2000    10     110   190,810  8,154,005 600,000  61,000
> 12 29/02/2000    20     460   177,050  8,333,120 600,000  69,000
> 13 08/03/2000     0   1,800   270,000  5,277,265 200,000  34,000
> 14 08/03/2000     2   1,800   403,380  9,237,105 490,000  80,000
> 15 08/03/2000    10   1,400   372,530 10,624,735 480,000  57,000
> 16 08/03/2000    20   3,100   261,215  6,228,160 340,000  37,000
> 17 14/03/2000     0   4,900   750,000 16,258,720 440,000  80,000
> 18 14/03/2000     2   4,900   633,895 10,952,305 380,000  54,000
> 19 14/03/2000    10   4,100   583,367 10,383,383 310,000  53,000
> 20 14/03/2000    20   8,200   653,945 10,148,210 380,000  48,000
> 21 21/03/2000     0     850   570,000 11,000,000 180,000 170,000
> 22 21/03/2000     2     850   520,000 27,000,000 130,000 190,000
> 23 21/03/2000    10   1,800   540,000 21,000,000 250,000 140,000
> 24 21/03/2000    20   1,800   470,000 10,000,000 110,000  70,000
> 25 27/03/2000     0   1,300   640,000 13,000,000 170,000  90,000
> 26 27/03/2000     2   1,300   770,000 17,000,000 230,000 120,000
> 27 27/03/2000    10     520   720,000 15,000,000 120,000 170,000
> 28 27/03/2000    20     130   620,000 12,000,000  98,000  74,000
> 29 04/04/2000     0   2,003   940,000 29,582,000 190,000  46,000
> 30 04/04/2000     2   2,003   952,400 27,186,525 210,000  67,000
> 31 04/04/2000    10   1,671   503,300 11,140,225  85,000  24,000
> 32 04/04/2000    20     863   682,550 14,605,825 140,000  32,000
> 33 07/04/2000     0   1,653   840,000 15,862,125 370,000  95,000
> 34 07/04/2000     2   1,653   819,350 13,099,600 280,000  67,000
> 35 07/04/2000    10   1,520   769,825 13,395,825 240,000  57,000
> 36 07/04/2000    20     422   784,700 10,910,700 170,000  28,000
> 37 12/04/2000     0   7,671   640,000  9,851,750 470,000 100,000
> 38 12/04/2000     2   7,671   600,625  9,339,400 490,000 170,000
> 39 12/04/2000    10   5,865   585,650  8,439,300 450,000 180,000
> 40 12/04/2000    20   1,276   595,225  7,297,150 360,000  92,000
> 41 14/04/2000     0  10,479   730,000 12,406,650 540,000 140,000
> 42 14/04/2000     2  10,479   700,000 10,406,650 490,000 110,000
> 43 14/04/2000    10   6,576   682,500  9,869,050 470,000 100,000
> 44 14/04/2000    20   3,307   739,075  8,875,250 420,000 180,000
> 45 16/04/2000     0   1,636   890,000  9,653,050 290,000 120,000
> 46 16/04/2000     2   1,636   885,725  9,934,300 300,000  97,000
> 47 16/04/2000    10   2,986   973,750 10,270,975 310,000 190,000
> 48 16/04/2000    20   1,222   629,250  6,792,500 210,000  90,000
> 49 19/04/2000     0     656   730,000 12,751,350 510,000 150,000
> 50 19/04/2000     2     656   831,575 13,673,700 400,000 120,000
> 51 19/04/2000    10     480   723,925 11,230,150 420,000 100,000
> 52 19/04/2000    20     872   671,975  9,858,900 330,000  97,000
> 53 27/04/2000     0     180 1,000,000 15,346,525 370,000  85,000
> 54 27/04/2000     2     180   926,800 22,825,400 670,000  93,000
> 55 27/04/2000    10       7   880,925 15,121,675 490,000  86,000
> 56 27/04/2000    20      64   723,100 10,638,400 230,000  21,000
> 
> 
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