Dhananjay wrote:
> Hello All,
>
> I have data set as follows:
>
> 24 GLU 3 47 LYS 6 3.909233 1
> 42 PRO 5 785 VAL 74 4.145114 1
> 54 LYS 6 785 VAL 74 4.305017 1
> 55 LYS 6 785 VAL 74 4.291098 1
> 56 LYS 7 785 VAL 74 3.968647 1
> 58 LYS 7 772 MET 73 4.385121 1
> 58 LYS 7 778 MET 73 4.422980 1
> 58 LYS 7 779 MET 73 3.954990 1
> 58 LYS 7 785 VAL 74 3.420554 1
> 59 LYS 7 763 GLN 72 4.431955 1
> 59 LYS 7 767 GLN 72 3.844037 1
> 59 LYS 7 785 VAL 74 3.725048 1
>
>
>
>
> I want to sort the data on the basis of 3rd column first and latter want
> to sort the sorted data (in first step) on the basis of 6th column.
>
> I tried sort() function but could not get the way how to use it.
>
> I am new to programming, please tell me how can I sort.
>
> Thanking you in advance ........
>>> data = """24 GLU 3 47 LYS 6 3.909233
1
... 42 PRO 5 785 VAL 74 4.145114 1
... 54 LYS 6 785 VAL 74 4.305017 1
... 55 LYS 6 785 VAL 74 4.291098 1
... 56 LYS 7 785 VAL 74 3.968647 1
... 58 LYS 7 772 MET 73 4.385121 1
... 58 LYS 7 778 MET 73 4.422980 1
... 58 LYS 7 779 MET 73 3.954990 1
... 58 LYS 7 785 VAL 74 3.420554 1
... 59 LYS 7 763 GLN 72 4.431955 1
... 59 LYS 7 767 GLN 72 3.844037 1
... 59 LYS 7 785 VAL 74 3.725048 1
... """
>>> rows = data.splitlines()
>>> rows.sort(key=lambda line: int(line.split()[5]))
>>> rows.sort(key=lambda line: int(line.split()[2]))
>>> print "\n".join(rows)
24 GLU 3 47 LYS 6 3.909233 1
42 PRO 5 785 VAL 74 4.145114 1
54 LYS 6 785 VAL 74 4.305017 1
55 LYS 6 785 VAL 74 4.291098 1
59 LYS 7 763 GLN 72 4.431955 1
59 LYS 7 767 GLN 72 3.844037 1
58 LYS 7 772 MET 73 4.385121 1
58 LYS 7 778 MET 73 4.422980 1
58 LYS 7 779 MET 73 3.954990 1
56 LYS 7 785 VAL 74 3.968647 1
58 LYS 7 785 VAL 74 3.420554 1
59 LYS 7 785 VAL 74 3.725048 1
Python's list.sort() is "stable". Therefore you can sort by the 6th column
first, and then by the third. Rows with the same value in the third column
will not change their relative position.
To calculate the value for the n-th row you can either use the above lambda
or the equivalent function:
def sixth_column(row):
columns = row.split() # split by whitespace
column = columns[5] # sixth column
return int(column) # convert to integer
If you don't convert to integer a row with "10" comes before a row with "2"
in the column which is probably not what you want.
Peter
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