#MATL, 8 bytes

'X&'''X&

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Input is a string enclosed in single quotes. If the string contains a single-quote symbol, it should be duplicated to escape it.

###Explanation

'X&'''   % Push string with the three characters used by the program. The single-quote 
         % symbol needs to be escaped by duplicating it
X&       % Take input implicitly. Set intersection. Display implicitly

MATL, 8 bytes

'X&'''X&

Try it online!

Input is a string enclosed in single quotes. If the string contains a single-quote symbol, it should be duplicated to escape it.

Explanation

'X&'''   % Push string with the three characters used by the program. The single-quote 
         % symbol needs to be escaped by duplicating it
X&       % Take input implicitly. Set intersection. Display implicitly

#MATL, 8 bytes

'X&'''X&

Try it online!

Input is a string enclosed in single quotes. If the string contains a single-quote symbol, it should be duplicated to escape it.

###Explanation

'X&'''   % Push string with the three characters used by the program. Single quote 
         % is escaped by duplicating it
X&       % Take input implicitly. Set intersection. Display implicitly

#MATL, 8 bytes

'X&'''X&

Try it online!

Input is a string enclosed in single quotes. If the string contains a single-quote symbol, it should be duplicated to escape it.

###Explanation

'X&'''   % Push string with the three characters used by the program. The single-quote 
         % symbol needs to be escaped by duplicating it
X&       % Take input implicitly. Set intersection. Display implicitly

#MATL, 8 bytes

'X&'''X&

Try it online!

Input is a string enclosed in single quotes. If the string contains a single-quote symbol, it should be duplicated to escape it.

###Explanation

'X&'''   % Push string with the three characters used by the program. Single quote 
         % is escaped by duplicating it
X&       % Take input implicitly. Set intersection. Display implicitly

#MATL, 8 bytes

'X&'''X&

Try it online!

Input is a string enclosed in single quotes. If the string contains a single-quote symbol, it should be duplicated to escape it.

###Explanation

'X&'''   % Push string with the three characters used by the program. Single quote 
         % is escaped by duplicating it
X&       % Take input implicitly. Set intersection. Display implicitly