ios - 未知转义序列 '\x20'

Question

我已经创建了这段代码

NSString *insertSQL = [NSString stringWithFormat:@"Update Expense_Group set Expense_sum = Expense_sum-\%@\ where Expense_Type_Id = \"%@\"",strExpAmount,current_Expense_TypeId];

现在，我收到了这个警告“未知转义序列'\x20' ”。

Answer 1

您只需要“ \”转义该“ stringWithFormat:”调用中的引号...

Answer 2

NSString *insertSQL = [NSString stringWithFormat:@"Update Expense_Group set Expense_sum = Expense_sum-'%@' where Expense_Type_Id = '%@'",strExpAmount,current_Expense_TypeId];

Answer 3

NSString *insertSQL = [NSString stringWithFormat:@"Update Expense_Group set Expense_sum = Expense_sum-%@ where Expense_Type_Id = %@",strExpAmount,current_Expense_TypeId];

这可以解决 %@ 之前不需要转义序列的问题。