[R] Splitting and arranging in ascending order

[Amelia Marsh]

Dear R forum

I have a data (actually its a big data and I am only giving part of my interest) as

my_dat = data.frame(instrument = c("EQ_0", "EQ_1", "EQ_10", "EQ_100", "EQ_2", "EQ_20", "IRS_0", "IRS_1", "IRS_10", "IRS_100", "IRS_2", "IRS_20"), mtm_value = c(23, 63, 8, 44, 68, 11, 83, 56, 73, 92, 14, 7))

> my_dat 
instrument mtm_value 
1        EQ_0     23 
2        EQ_1     63 
3       EQ_10    8 
4      EQ_100   44 
5        EQ_2     68 
6       EQ_20    11 
7       IRS_0    83 
8       IRS_1    56 
9      IRS_10   73 
10    IRS_100        92 
11      IRS_2   14 
12     IRS_20   7

I need to split the first column and arrange the output in the ascending order as shown below :

  instrument sr_no   mtm_value 

1          EQ          0      23 
2          EQ          1      63 
3          EQ          2      68 
4          EQ         10       8 
5          EQ         20      11 
6          EQ        100      44 
7         IRS         0      83 
8         IRS         1      56 
9         IRS         2      14 
10        IRS       10      73 
11        IRS       20       7 
12        IRS      100      92

I tried to use gsub, strsplit  but doesn't give me the required output.

Kindly guide

Regards

Amelia