Problem with which function

Hej,

i need the which() funktion to find the positions of an entry in a
matrix.

the entries i'm looking for are : seq(begin,end,0.01) and there are no
empty spaces
i'm searching in the right range.

so i was looking for the results R can find and i recieved this answer.

for (l in
1:length(qr)){print(c(l,nstu[l,1],nsto[l,1],nsto[l,1]-nstu[l,1],(nsto[l,1]-nstu[l,1])*100,which(sp1[,1]==nstu[l,1]),(nsto[l,1]-nstu[l,1])*100+which(sp1[,1]==nstu[l,1]),which(r[,1]==nstu[l,1]),(nsto[l,1]-nstu[l,1])*100+which(r[,1]==nstu[l,1])))}
[1] 1 0 0 0 0
[1] 2 0 0 0 0
[1] 3 0 0 0 0
[1]    4.00   87.34   87.97    0.63   63.00 2491.00 2554.00 2491.00
2554.00
[1]    5.00   86.73   88.46    1.73  173.00 2430.00 2603.00
[1]    6.00   86.22   88.77    2.55  255.00 2379.00 2634.00
[1]    7.00   85.77   89.01    3.24  324.00 2334.00 2658.00
[1]    8.00   85.36   89.22    3.86  386.00 2293.00 2679.00
[1]    9.0   85.0   89.4    4.4  440.0 2257.0 2697.0
[1]   10.00   84.68   89.57    4.89  489.00 2225.00 2714.00 2225.00
2714.00
[1]   11.00   84.38   89.73    5.35  535.00 2195.00 2730.00
[1]   12.00   84.11   89.88    5.77  577.00 2168.00 2745.00
[1]   13.00   83.86   90.02    6.16  616.00 2143.00 2759.00
[1]   14.00   83.64   90.15    6.51  651.00 2121.00 2772.00
[1]   15.00   83.43   90.28    6.85  685.00 2100.00 2785.00 2100.00
2785.00
[1]   16.00   83.24   90.40    7.16  716.00 2081.00 2797.00
[1]  17.00  83.07  90.52   7.45 745.00
[1]   18.00   82.91   90.63    7.72  772.00 2048.00 2820.00
[1]   19.00   82.76   90.75    7.99  799.00 2033.00 2832.00
[1]   20.00   82.62   90.86    8.24  824.00 2019.00 2843.00 2019.00
2843.00
[1]   21.00   82.49   90.97    8.48  848.00 2006.00 2854.00
[1]   22.00   82.37   91.08    8.71  871.00 1994.00 2865.00 1994.00
2865.00
[1]   23.00   82.26   91.19    8.93  893.00 1983.00 2876.00
[1]   24.00   82.16   91.31    9.15  915.00 1973.00 2888.00
[1]   25.00   82.07   91.42    9.35  935.00 1964.00 2899.00
[1]   26.00   81.98   91.53    9.55  955.00 1955.00 2910.00
[1]   27.00   81.90   91.64    9.74  974.00 1947.00 2921.00 1947.00
2921.00
[1]   28.00   81.83   91.75    9.92  992.00 1940.00 2932.00
[1]   29.00   81.76   91.87   10.11 1011.00 1933.00 2944.00
[1]   30.00   81.69   91.98   10.29 1029.00 1926.00 2955.00
[1]   31.00   81.63   92.09   10.46 1046.00 1920.00 2966.00
[1]   32.00   81.57   92.20   10.63 1063.00
[1]   33.00   81.50   92.31   10.81 1081.00 1907.00 2988.00
[1]   34.00   81.44   92.43   10.99 1099.00 1901.00 3000.00
[1]   35.00   81.38   92.54   11.16 1116.00 1895.00 3011.00
[1]   36.00   81.31   92.65   11.34 1134.00 1888.00 3022.00
[1]   37.00   81.25   92.76   11.51 1151.00 1882.00 3033.00
[1]   38.00   81.18   92.87   11.69 1169.00 1875.00 3044.00 1875.00
3044.00
[1]   39.00   81.12   92.98   11.86 1186.00 1869.00 3055.00 1869.00
3055.00
[1]   40.00   81.05   93.10   12.05 1205.00 1862.00 3067.00
[1]   41.00   80.99   93.21   12.22 1222.00 1856.00 3078.00
[1]   42.00   80.92   93.32   12.40 1240.00 1849.00 3089.00
[1]   43.00   80.86   93.43   12.57 1257.00 1843.00 3100.00
[1]   44.00   80.79   93.54   12.75 1275.00
[1]   45.00   80.73   93.66   12.93 1293.00 1830.00 3123.00
[1]   46.00   80.66   93.77   13.11 1311.00 1823.00 3134.00
[1]   47.00   80.60   93.88   13.28 1328.00 1817.00 3145.00
[1]   48.00   80.53   93.99   13.46 1346.00 1810.00 3156.00
[1]   49.00   80.47   94.10   13.63 1363.00 1804.00 3167.00
[1]   50.00   80.40   94.22   13.82 1382.00 1797.00 3179.00 1797.00
3179.00
[1]   51.00   80.34   94.33   13.99 1399.00 1791.00 3190.00 1791.00
3190.00
[1]   52.00   80.27   94.44   14.17 1417.00 1784.00 3201.00
[1]   53.00   80.20   94.55   14.35 1435.00 1777.00 3212.00
[1]   54.00   80.14   94.66   14.52 1452.00 1771.00 3223.00
[1]   55.00   80.07   94.77   14.70 1470.00 1764.00 3234.00
[1]   56.00   80.01   94.89   14.88 1488.00 1758.00 3246.00
[1]   57.00   79.94   95.00   15.06 1506.00 1751.00 3257.00
[1]   58.00   79.87   95.11   15.24 1524.00 1744.00 3268.00 1744.00
3268.00
[1]   59.00   79.81   95.22   15.41 1541.00 1738.00 3279.00
[1]   60.00   79.74   95.32   15.58 1558.00 1731.00 3289.00
[1]   61.00   79.67   95.43   15.76 1576.00 1724.00 3300.00
[1]   62.00   79.61   95.54   15.93 1593.00 1718.00 3311.00
[1]   63.00   79.54   95.65   16.11 1611.00
[1]   64.00   79.47   95.76   16.29 1629.00 1704.00 3333.00
[1]   65.00   79.41   95.87   16.46 1646.00 1698.00 3344.00
[1]   66.00   79.34   95.97   16.63 1663.00 1691.00 3354.00 1691.00
3354.00
[1]   67.00   79.27   96.08   16.81 1681.00 1684.00 3365.00
[1]   68.00   79.21   96.19   16.98 1698.00 1678.00 3376.00 1678.00
3376.00
[1]   69.00   79.14   96.30   17.16 1716.00 1671.00 3387.00
[1]   70.00   79.07   96.40   17.33 1733.00 1664.00 3397.00
[1]   71.00   79.01   96.51   17.50 1750.00 1658.00 3408.00

as it is obvious there are a lot of numbers for r, where R find nothing
and some in sp1 where r find nothing.

and here some more informations to my curiosity:

nstu[10,1]

[1] 84.68

r[2225,1]

[1] 84.68

is(r)

[1] "matrix"    "array"     "structure" "vector"

is(nstu)

[1] "matrix"    "array"     "structure" "vector"

nstu[11,1]

[1] 84.38

r[2195,1]

[1] 84.38

which(r==nstu[10,1])

[1] 2225

which(r==nstu[11,1])

integer(0)

why is it like that?

Thanks for a answer

max