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8.2.23 ismissing ¶

Function: out = ismissing (X) ¶

Function: out = ismissing (X, indicator) ¶

Find missing values.

Determines which elements of X contain missing values. If an indicator input is not provided, standard missing values depending on the input type of X are used.

Standard missing values depend on the data type:

• NaN for double, single, duration, and calendarDuration
• NaT for datetime
• ' ' for char
• {''} for cellstrs
• Integer numeric types have no standard missing value; they are never considered missing.
• Structs are never considered missing.
• Logicals are never considered missing.
• Other types have no standard missing value; it is currently an error to call ismissing on them without providing an indicator.
  • This includes cells which are not cellstrs; calling ismissing on them results in an error.
  • TODO: Determine whether this should really be an error, or if it should default to never considering those types as missing.
  • TODO: Decide whether, for classdef objects, ismissing should polymorphically detect isnan()/isnat()/isnanny() methods and use those, or whether we should require classes to override ismissing() itself.

If indicator is supplied, it is an array containing multiple values, all of which are considered to be missing values. Only indicator values that are type-compatible with the input are considered; other indicator value types are silently ignored. This is by design, so you can pass an indicator that holds sentinel values for disparate types in to ismissing() used for any type, or for compound types like table.

Indicators are currently not supported for struct or logical inputs. This is probably a bug.

Table defines its own ismissing() method which respects individual variables’ data types; see table.ismissing.