Sorting column labels by numeric in string, Python

Question

I have successfully connected Python to Microsoft Access Database. The problem appears when I am trying to sort the column labels in the data frame by number in increasing order. The column names also contain characters.

I have looked into several sorting functions, but none of them seems to work for this issue.

My data frame is as follows;

C1  C10  C11  C12  C13  C14 ... C2  C20  C21 ... C3 ...

How I want my columns to be sorted;

C1  C2  C3  C4  C5  C6  C7  C8  C9  C10  C11 ...

My data frame also contain other component, such as benzene, toluene, etc, so I would like the list to be in alphabetic order too.

Moreover, is there a way to sort it as;

... C4   C5   iC5   nC5   C6   iC6   nC6.

The above question is most important, but if someone know if/how this can be done, please advice be!

On beforehand, thanks for your help!

Answer 1

I think this might be answer you are looking for:

data.reindex_axis(sorted(data.columns, key=lambda x: float(x[1:])), axis=1)

You can freely modify the value in x[1:] to include or exclude more characters in the string.

Answer 2

For the first case, you could do the following.

df = df[list(sorted(df.columns.tolist()))]

For the second case, maybe reversing the strings could work.

rev = lambda cols: list(map(lambda x: "".join(list(reversed(x))), cols)) 
cols = df.columns.tolist()
df = df[rev(list(sorted(rev(df.columns.tolist()))))]