我们能用hadoop运行现有的程序吗？或者我们只需要用mapreduce样式修改它？

Question

我写了下面的python程序来处理excel文件中的数据。但是现在有没有可能用hadoopmapreduce运行相同的程序，传统的程序和mapreduce程序有何不同？你知道吗

import xlrd

with xlrd.open_workbook('interference.xlsx') as book:
# 0 corresponds for 1st worksheet, usually named 'Book1'
sheet = book.sheet_by_index(0)

# gets col C values
B = [ B for B in sheet.col_values(1) ]


# gets col D values
D = [ D for D in sheet.col_values(3) ]


# combines D and E elements to tuples, combines tuples to list
# ex. [ ('Incoming', 18), ('Outgoing', 99), ... ]
data = list( zip(B,D) )

# gets total no of get request attempts for each UID

x=1
for uid in data:
    while x <=44 :
        attempts = sum( tup[1] for tup in data if tup[0] == x )
        print("Total attempts for UID",x, attempts)
        x=x+1

Answer 1

在Hadoop中不可能运行与MapReduce作业相同的程序。你知道吗

MapReduce是一种编程范式，其思想是将计算分为两个阶段：第一阶段（mapping）将问题分解为多个子问题，并对每个子问题进行求解；第二阶段（reduce）将子问题的所有结果汇总在一起，得到最终解。你知道吗

我建议您看看WordCount程序，它是Hadoop的helloworld:http://wiki.apache.org/hadoop/WordCount