如何使用startswith函數生成像diff工具中的輸出？

Question

請幫我解決（我覺得有趣）算法問題。 我今天花了一整天時間（迷路）來解決這個問題。 這是我的代碼：

rman_config = ('''CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
''')

rman_new_parameters = [('RETENTION POLICY', 'TO RECOVERY WINDOW OF 2 DAYS'),
                       ('CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE', 'DISK TO controlfile_%F'),
                       ('CONTROLFILE AUTOBACKUP', 'ON'),
                       ('DEVICE TYPE', 'DISK PARALLELISM 4 BACKUP TYPE TO BACKUPSET')]

tuple_to_search = tuple([i[0] for i in rman_new_parameters])

for line in rman_config.splitlines():
    if line.startswith(tuple_to_search, 10):
        print('-  ' + line)
        print('+  CONFIGURE ' + '[parameter] ' + '[new value]' + ';')
    else:
        print('   ' + line)

哪里：

• rman_config - 具有默認配置的變量
• rman_new_parameters - 以隨機順序覆蓋默認值的新參數，其中：
  • 元組中的第一個元素是一個參數（即CONTROLFILE AUTOBACKUP ）
  • 元組中的第二個元素是一個新值（即ON ）

到目前為止我有這個輸出：

-  CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
+  CONFIGURE [parameter] [new value];
   CONFIGURE BACKUP OPTIMIZATION OFF; # default
   CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
-  CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
+  CONFIGURE [parameter] [new value];
-  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
+  CONFIGURE [parameter] [new value];
-  CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
+  CONFIGURE [parameter] [new value];
   CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default

但我想要這個（就像在Diff ）：

-  CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
+  CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 2 DAYS;
   CONFIGURE BACKUP OPTIMIZATION OFF; # default
   CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
-  CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
+  CONFIGURE CONTROLFILE AUTOBACKUP ON;
-  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
+  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO cf_%F;
-  CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
+  CONFIGURE DEVICE TYPE DISK PARALLELISM 4 BACKUP TYPE TO BACKUPSET;
   CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default 

startswith函數很棒，但它沒有告訴我哪個元組被識別（只返回True或False）。 我上面代碼的問題是如何映射以下行：

if line.startswith(tuple_to_search, 10):

如果它對rman_new_parameters列表是真的。

我還沒有弄清楚如何解決它？ 我會非常感激任何幫助。

Answer 1

for line in rman_config.splitlines():
    for params in rman_new_parameters:
        if line.startswith(params[0], 10):
            print('-  {}'.format(line))
            print('+  CONFIGURE {} {}'.format(*params))
            break
    else:
        print('   {}'.format(line))

基本上，我沒有將元組傳遞給.startswith ，只是在一個循環中逐個測試。

另外， for + else 。

Answer 2

我不知道你要做什么。 但無論如何我寫代碼。 看看這個答案是否符合您的問題。 主要區別在於你的if-else塊變為try-except塊。 並且重點是index函數，它返回tuple_to_search第一次出現參數的tuple_to_search 。 我假設rman_new_parameters所有參數值都是從rman_config更改的。

rman_config = ('''CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
''')

rman_new_parameters = [('RETENTION POLICY', 'TO RECOVERY WINDOW OF 2 DAYS'),
                       ('CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE', 'DISK TO controlfile_%F'),
                       ('CONTROLFILE AUTOBACKUP', 'ON'),
                       ('DEVICE TYPE', 'DISK PARALLELISM 4 BACKUP TYPE TO BACKUPSET')]

tuple_to_search = [i[0] for i in rman_new_parameters]

for line in rman_config.splitlines():
    try:
        index = [line.startswith(tup, 10) for tup in tuple_to_search].index(True)
        print('-  ' + line)
        print('+  CONFIGURE ' + " ".join(rman_new_parameters[index]) + ';')
        #Add these if you don't need to check parameter once matched.
        #del rman_new_parameters[index]
        #del tuple_to_search[index]
    except:
        print('   ' + line)

輸出：

-  CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
+  CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 2 DAYS;
   CONFIGURE BACKUP OPTIMIZATION OFF; # default
   CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
-  CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
+  CONFIGURE CONTROLFILE AUTOBACKUP ON;
-  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
+  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO controlfile_%F;
-  CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
+  CONFIGURE DEVICE TYPE DISK PARALLELISM 4 BACKUP TYPE TO BACKUPSET;
   CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default

PS

我的輸出與您想要的輸出略有不同（2行不同）。 我不知道為什么。 所以請確保它是您想要的輸出。

你：

...
+  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO cf_%F;
...
   CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default 

礦：

...
+  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO controlfile_%F;
...
   CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
                                                                        ^
                                                                    no space here