本文將會分析一個檔案合併的程式，並指出在合併檔案過程中需要注意的問題。
下面是需要合併的檔案示例：

分析思路：
要將兩個檔案合併，首先要將檔案讀到記憶體中，成為列表。再將列表分割，按照類別將資料分開儲存，即姓名、電話、郵箱。通過遍歷列表1，依次與列表2比較，如果二者有重合的人，那麼直接利用 .join([ ])姓名電話郵箱合併到一行，儲存到另外一個列表變數裡面。二者不重合的人，說明只有列表1中才有，故將此人的郵箱資訊用str(‘—–’)代替。
經過這次遍歷之後，列表1中所有的人和列表2中與列表1中重複的人，都重新整合到了新的列表變數裡面。接下來還需要把列表2中特有的人，新增到新的列表變數中。方法是遍歷列表2，把與列表1不重合的人取出來儲存。
最後要將新的列表變數中的資料寫入到新的檔案中，並關閉所有檔案。
流程圖如下：

"""
Created on Fri Aug  4 12:59:36 2017

@author: 13323
"""
# This program can combine two or more files into one file.
def main():
    #firstly open the files
    data1 = open("test_3.txt","rb")
    data2 = open("test_4.txt","rb")

    # read the data in file into list
    data1.readline() #only read one line, skip the first line
 

    data2.readline() #only read one line, skip the first line
    file1 = data1.readlines() #read all variable into list file1 
    file2 = data2.readlines() #read all variable into list file2
    #print(file1)

    #define particular list to store variable
    file1_name = []
    file1_tel = []
    file2_name = []
    file2_email = []
    #file3 = []
 


    #split file1 into two part
    for line in file1:
        element = line.split() #line.split(); devide by ' '
        file1_name.append(str(element[0].decode('gbk')))
        file1_tel.append(str(element[1].decode('gbk')))

    #split file2 into two part
    for line in file2:
        element = line.split()
        file2_name.append(str(element[0].decode('gbk')))
        file2_email.append(str(element[1].decode('gbk')))

    # pick up the name in the file1 same as the name in the file2 and combine 
    file3 = []
    for i in range(len(file1_name)):
        s = ''
        if file1_name[i] in file2_name:
            j = file2_name.index(file1_name[i])
            s = '\t'.join([file1_name[i],file1_tel[i],file2_email[j]])
            s += '\n'
        else:
            s = '\t'.join([file1_name[i],file1_tel[i],str("----")])
            s += '\n'
        file3.append(s)

    #pick up the name in the file1 doesn't same as the name in the file2 
    for i in range(len(file2_name)):
        s = ''
        if file2_name[i] not in file1_name:
            s = '\t'.join([file2_name[i],str('----'),file2_email[i]])
            s += '\n'
        file3.append(s)

    #write the data into file3 
    data3 = open("test_5.txt","w")
    data3.writelines(file3)

    #close the file
    data1.close()
    data2.close()
    data3.close()

main()

關鍵點：
編碼與解碼
列表合併與拆解