php - 值错误 : need more than 0 values to unpack error in Python

Question

今天尝试在Linux下执行如下命令，想测试hadoop中的Streaming接口(interface)，

 cat test.txt|php wc_mapper.php|python Reducer.py

发生错误:

"Traceback (most recent call last):
 File "Reducer.py", line 7, in <module>
word,count = line.split()   
ValueError: need more than 0 values to unpack
"

test.txt 的内容如下:

hello world
hello world
hello world

PHP编写的wc_mapper.php的内容是

#!/usr/bin/php
<?php
error_reporting(E_ALL ^ E_NOTICE);
$word2count = array();
while (($line = fgets(STDIN)) !== false) {
      $line = trim($line);
      $words = preg_split('/\W/', $line, 0, PREG_SPLIT_NO_EMPTY);
      foreach ($words as $word) {
                echo $word, chr(9), "1", PHP_EOL;
      }
}
?>

而由 Python 编写的 Reducer.py 的内容是

#!/usr/bin/python
from operator import itemgetter
import sys
word2count = {}
for line in sys.stdin:
   line = line.strip()
   word,count = line.split()
   try:
      count = int(count)
      word2count[word] = word2count.get(word, 0) + count
   except ValueError:
      pass

sorted_word2count = sorted(word2count.items(), key=itemgetter(0))
for word,count in sorted_word2count:
   print '%s\t%s'%(word,count)

谁知道错误的原因，如何解决这个问题？
当我执行第一部分命令时

cat test.txt|php wc_mapper.php|sort

，我得到以下输出:

hello   1
hello   1
hello   1
world   1
world   1
world   1

第一行为空，但占一行。

Answer 1

在 split() 中提供分隔符功能

   try:    
        word,count = line.split(" ") 
   except:
        print("Error")

我已将单个空格作为分隔符。你可以相应地改变。