`isfield`

Tests whether a struct has the given field names.

Category: Language Fundamentals > Data Types

Syntax

tf = isfield(S, name)

Returns true if S is a struct with a field called name.

tf = isfield(S, names)

Checks several names at once and returns one logical per name.

Description

isfield compares names exactly, including case. It never errors on a non-struct first argument, it just answers false, which makes it safe for checking optional fields of unknown input.

A name that is not text, inside the cell array, also yields false for that position instead of an error.

Input arguments

S: Value to test. If it is not a struct the result is false.
name, names: Character vector, string scalar, or cell array of names.

Output arguments

tf: Logical scalar for one name, or a logical array the same size as the cell array names.

Example

Checking one and several fields

s.a = 1;
s.b = 'x';
isfield(s, 'a')
isfield(s, {'a', 'c', 'b'})
isfield(5, 'a')

Output

ans = logical
   1
ans = 1×3 logical array

   1   0   1
ans = logical
   0

isfield