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Secrets of Excel. Checking the input data.

as a situation, fill even the most complex spreadsheet of problems does not amount to. It is much more difficult not to mess with mistakes. After all, you see, it's easy to make a mistake by typing, for example, 1899, in exchange for 1999, or to make a mistake in typing impressive numbers. In the popular Microsoft Excel spreadsheet, there are several tricks that make it easier to enter data and also automatically verify that they are correct.

When entering numeric data, it is allowed to set a period of conditions for checking the entered values. In this case, for each entered value, a check will be made to see if it is within the specified interval. If this condition fails, a message appears on the screen stating that the entered value does not fit the specified limits in any way.
In order to specify a condition for checking numeric values, it is necessary to select the range of cells where numbers will be entered, also select "Data -> Validation". In the "Data type" field, you must set whole numbers or valid ones, depending on what you plan to place in the cell. The "valid" type is used for numbers with a decimal point. Below, the "value" field specifies a logical condition, for example "between", "more", "greater than or equal to", "not equal to". The last pair of fields is for numeric values, with which the input data will be compared.

Here you specify the conditions for checking numeric values.
Excel makes it much easier to enter data that is repeated. Enter all the name data in a separate region of the worksheet. Later, selecting the range of future value verification, select "Data -> Validation", in the "Data type" field, set the value to "List". Below in the line "Source" you need to specify the addresses of cells in which this list is located.

When using the list for data entry, you must specify the address of the range in which it is located.
As a result of these actions, you do not need to enter text in the selected cells: when the cell is activated, a list appears next to it, from which you just need to select the desired value.

Instead of entering data now allowed to select them from the list.
Another convenient solution: in Excel, you can eat the ability to set the prompt displayed next to the cell when you enter data into it. To do this, in the "Check Input Values" window, you must go to the "Message for Input" tab and also type the message that will appear when you enter data into the cell. It will be convenient to use the "Show hint, if the cell is current" switch.

The hint helps you to specify what exactly is entered in the cell.
The "Error message" tab allows you to control the appearance of a standard system message that tells the user that the data was entered incorrectly. You can turn off its appearance (uncheck "Show error message"), but it's similarly allowed to set your own text of this message in the "Title" fields as well as "Message".