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isKey (Map) - Check if containers.Map contains key

Syntax

tf = isKey(M, keys)

Description

tf = isKey(M, keys) looks for the specified keys in the Map instance M, and returns logical 1 (true ) for those elements that it finds, and logical 0 (false) for those it does not. keys is a scalar key or cell array of keys. If keys is nonscalar, then return value tf is a nonscalar logical array that has the same dimensions and size as keys.

Read more about Map Containers in the MATLAB Programming Fundamentals documentation.

Examples

Construct a Map object where the keys are states in the United States and the value associated with each key is that state's capital city:

US_Capitals = containers.Map( ...
{'Arizona', 'Nebraska', 'Nevada', 'New York', ...
 'Georgia', 'Alaska', 'Vermont', 'Oregon'}, ...
{'Phoenix', 'Lincoln', 'Carson City', 'Albany', ...
 'Atlanta', 'Juneau', 'Montpelier', 'Salem'})

Check three states to see if they are in the map:

isKey(US_Capitals, {'Georgia', 'Alaska', 'Wyoming'})
ans =
     1     1     0

Check two states and a capital to see if they are all keys in the map:

isKey(US_Capitals, {'Georgia'; 'Montpelier'; 'Alaska'})
ans =
     1     0     1

Identify the capital city of a specific state, but only attempt this if you know that this state is in the map:

S = 'Nebraska';
if isKey(US_Capitals, S)
sprintf('   The capital of %s is %s', S, US_Capitals(S))
else error('The state of %s is not in the map', S)
end
ans =
   The capital of Nebraska is Lincoln

S =  Montana';
if isKey(US_Capitals, S)
sprintf('   The capital of %s is %s', S, US_Capitals(S))
else error('The state of %s is not in the map', S)
end

??? The state of Montana is not in the map

See Also

containers.Map, keys(Map), values(Map), size(Map), length(Map), remove(Map), handle

isjava

iskeyword

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