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迭代和替换槽双阵列(Iteration and replace through double array)

 如果之前询问过，先抱歉。  
 拥有这个数组：  
a = [1, None, 2], [3, 4, 5], [6, None, 7]
 
 我需要替换None的值为0.我的第一个实现是通过数组，但我想在一行中完成。  
 我尝试过这样的，但没有工作：  
a = [0 if value is None else value for value in a[i][1] for i in range(len(a))]
 
 显然不工作，那么正确的方法是什么？  
 编辑：我不想触摸其他位置，只是在arrya中的每个元素的第二个位置。  
 这个：  
a = [None, None, 2], [3, 4, 5], [6, None, 7]
 
 将返回这个：  
a = [None, 0, 2], [3, 4, 5], [6, 0, 7]

Having this array: 
a = [1, None, 2], [3, 4, 5], [6, None, 7]
 
I need to replace the values of None for 0. My first implementation is to go trough the array, but I want to do it in one line. 
I tried something like this, but didn't work: 
a = [0 if value is None else value for value in a[i][1] for i in range(len(a))]
 
Obviously is not working, what would be the right approach? 
Edit: I don't want to touch the other positions, just the second position of every element in the array. 
This: 
a = [None, None, 2], [3, 4, 5], [6, None, 7]
 
Will return this: 
a = [None, 0, 2], [3, 4, 5], [6, 0, 7]

原文：https://stackoverflow.com/questions/19281500

更新时间：2023-01-09 09:01

最满意答案

 确保指向SQlite数据库的位置正确。在执行查询之前，请确保表处于打开状态并准备好进行操作。 参考此代码：  
        sqlite3_stmt    *statement;
        sqlite3 *cPDB;
        NSString *docsDir;
        NSArray *dirPaths;

        dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

        docsDir = [dirPaths objectAtIndex:0];
         // Data base path 
        databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: @"cPDB.db"]];

     const char *dbpath = [databasePath UTF8String];

if (sqlite3_open(dbpath, &cPDB) == SQLITE_OK)
    {

        NSString *querySQL = [NSString stringWithFormat: @"UPDATE USER_SESSION_INFO SET \"%@\" = \"%@\", synState = 'false' WHERE sessionName=\"%@\"",categoryTy,state,sessionName];


        const char *query_stmt = [querySQL UTF8String];

        if (sqlite3_prepare_v2(cPDB, query_stmt, -1, &statement, NULL) == SQLITE_OK)
        {
            if((sqlite3_step(statement)) != SQLITE_DONE)
                NSLog(@"Not Updated");
            else
            {
                NSLog(@"Succesfully updated row !");
                return YES;
            }
        } 

    } 

Found the problem. There were no single quotes around ?8 in the update statement. Well, its always the small problems. Thanks everyone!

迭代和替换槽双阵列(Iteration and replace through double array)

最满意答案

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