未知的转义序列'\ x20'

Question

我已创建此代码

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

现在，我收到此警告“未知转义序列'\ x20'”。

Answer 1

您只需要“\”在“stringWithFormat:”通话中转义引号...

Answer 2

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。

Answer 3

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