Sorting a csv file in Python

Question

I am attempting to sort my csv file by a specific column. That is easy enough with this below code:

with open("outfile.csv","rb") as infile,open("outfile.csv","wb") as outfile:
    reader= csv.reader(infile,delimiter=',')
    writer= csv.writer(outfile)
    sort= sorted(reader,key=operator.itemgetter(7), reverse= True)
    for eachline in sort:
        writer.writerow(eachline)

In my example however, it will sort but will sort in an odd way. For example, it would return the file to me descending in this order: 3.8,3.7,3.1,21.7,21.6,2.8.

Since this is causing me an issue, I would like to fix this; if it can't, instead I'd like to sort by largest length if that is possible.

This sounds confusing but this is the issue I am having. Any help would be great.

Thank you.

Answer 1

尝试对float值而不是str值进行排序：

sort= sorted(reader,key=lambda x:float(x[7]), reverse= True)