isfield

Determine if input is structure array field

Syntax

TF = isfield(S,field)

Description

TF = isfield(S,field) returns 1 if field is the name of a field of the structure array S. Otherwise, it returns 0.

If field is an array that contains multiple names and S is a structure array, then TF is a logical array that has the same size.

If S is not a structure array, then isfield returns 0.

Examples

Determine If Input Names Are Field Names

Create a structure.

S.x = linspace(0,2*pi);
S.y = sin(S.x);
S.title = 'y = sin(x)'

S = struct with fields:
        x: [0 0.0635 0.1269 0.1904 0.2539 0.3173 0.3808 0.4443 0.5077 0.5712 0.6347 0.6981 0.7616 0.8251 0.8885 0.9520 1.0155 1.0789 1.1424 1.2059 1.2693 1.3328 1.3963 1.4597 1.5232 1.5867 1.6501 1.7136 1.7771 1.8405 1.9040 1.9675 ... ] (1x100 double)
        y: [0 0.0634 0.1266 0.1893 0.2511 0.3120 0.3717 0.4298 0.4862 0.5406 0.5929 0.6428 0.6901 0.7346 0.7761 0.8146 0.8497 0.8815 0.9096 0.9341 0.9549 0.9718 0.9848 0.9938 0.9989 0.9999 0.9969 0.9898 0.9788 0.9638 0.9450 0.9224 ... ] (1x100 double)
    title: 'y = sin(x)'

Determine if 'title' is the name of a field of S.

TF = isfield(S,'title')

TF = logical
   1

You can test multiple names in one call to the isfield function by specifying them in a cell array or string array.

field = {'x','y','z','title','error'};
TF = isfield(S,field)

TF = 1x5 logical array

   1   1   0   1   0

Input Arguments

S — Structure array

structure array

Structure array.

field — Potential field names

character vector | cell array of character vectors | string array

Potential field names, specified as a character vector, cell array of character vectors, or string array.

Tips

• If the input argument S is an object, then isfield always returns 0, even when field is the name of a property.

  To determine if a name is the name of a property of an object, use the isprop function.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• Cell arrays are not supported for the second argument.

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

Version History

Introduced before R2006a