どのように各行のフィールドのlenで行を並べ替えることができますか？ Python

Question

10行を最短から最長の昇順にソートして出力するコードが1つあります。私はテストテキストを持っていますが、私は位置行[4]のフィールドのlenを使って出力行を並べ替えることを望みますが、私はテキスト全体を読む必要があると思うので、それを行う方法はわかりません第5フィールドの長さの関数としての線。

#!/usr/bin/python 
import sys 
import csv 


def mapper(): 
    reader = csv.reader(sys.stdin, delimiter='\t') 
    writer = csv.writer(sys.stdout, delimiter='\t', quotechar='"', quoting=csv.QUOTE_ALL) 

    for line in reader: 
      line.sort(key=len) 
      writer.writerow(line) 



test_text = """\"\"\t\"\"\t\"\"\t\"\"\t\"333\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"88888888\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"1\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"11111111111\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"1000000000\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"22\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"4444\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"666666\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"55555\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"999999999\"\t\"\" 
\"\"\t\"\"\t\"\"\t\"\"\t\"7777777\"\t\"\" 
""" 

# This function allows you to test the mapper with the provided test string 
def main(): 
    import StringIO 
    sys.stdin = StringIO.StringIO(test_text) 
    mapper() 
    sys.stdin = sys.__stdin__ 
main() 

私は最終的な結果であることを望む：

"" "" "" "" "22" "" 
"" "" "" "" "333" "" 
"" "" "" "" "4444" "" 
"" "" "" "" "55555" "" 
"" "" "" "" "666666" "" 
"" "" "" "" "7777777" "" 
"" "" "" "" "88888888" "" 
"" "" "" "" "999999999" "" 
"" "" "" "" "1000000000" "" 
"" "" "" "" "11111111111" "" 

私はこれをどのように行うことができますか？

Answer 1

変更ソートのラインのためのこの

def mapper(): 
    reader = csv.reader(sys.stdin, delimiter='\t') 
    writer = csv.writer(sys.stdout, delimiter='\t', quotechar='"', quoting=csv.QUOTE_ALL) 

    for line in sorted(list(reader), key=lambda x: len(x[-2])): 
     writer.writerow(line)