A field name, as long as the field type matches the argument type (string, number, or date).In the tables below, any argument can be as follows: The expression would be TOTALPOP / NULLIF(POP18, 0).įunctions take arguments. You can guard against this using the NULLIF function described below. If any feature has a POP18 equal to zero, the calculation will result in a divide-by-zero error. For example, suppose you need to calculate a double field to be TOTALPOP divided by POP18. Functions work with field names, literals, and other functions. In addition to simple expressions using operators, you can also use functions. If you click a field name in the Fields list, the field is added to the expression.If you hover over a field name in the Fields list, the field alias and field type are displayed.You can filter this list by the field types String, Numeric, and Date. The Fields list shows you all the field names available for calculations. Calculate Field works only with field names, not field aliases.If you have a filter on your layer, only the records that meet the filter criteria.The following are additional considerations: If there are any errors, an error message will appear at the bottom of the dialog box. Do not use a double quotation mark.Īfter you've created your expression, click the Calculate button. To include an apostrophe in the string, use two single quotation marks for the apostrophe.See Numeric functions below for information on the CAST function. For example, if you're calculating a double field named POP to an integer field named SAMPLE, the expression will appear as CAST(SAMPLE AS FLOAT). If you are calculating a field of type double to field of type integer, the CAST function may be automatically added to your expression.
You'll need to use the string functions described in the String functions section. Math operators do not work with string fields.For more complex equations, you can use the parentheses to specify the order of calculations, for example, SAMPLE * (BASELINE - 40).To multiply all values in a numeric field named SAMPLE by 100.0, type SAMPLE * 100.0 for the expression.On the Calculate Field dialog box, you can build simple expressions using operators such as plus, minus, multiply, and divide.
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