Java: How to check if a Key is mapped in a HashMap?

Question

How do I check if a Key is mapped in a HashMap?

Here is my code:

 currencyMap = new HashMap<String, String>(); currencyMap.put("USD", "US Dollar"); currencyMap.put("EUR", "Euro"); currencyMap.put("GBP", "British Pound Sterling"); currencyMap.put("JPY", "Japanese Yen"); currencyMap.put("CAD", "Canadian Dollar"); currencyMap.put("AUD", "Australian Dollar"); String checkCurrency = "CHF"; // Swiss Franc // List Keys for (String key : currencyMap.keySet() ) { String value = currencyMap.get( key ); System.out.println( key + " = " + value); }

René Link · Accepted Answer · 2013-12-21 14:03:07Z

2

Use

boolean isMapped = currentMap.containsKey(checkCurrency);

answered Dec 21, 2013 at 14:03

René Link

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Konstantin Yovkov · Accepted Answer · 2013-12-21 14:14:50Z

When you have questions like these in the future, try to find the HashMap javadoc and then you will be able to determine very quickly what to use.

In this case you can use HashMap#containsKey(java.lang.Object) or if you want to find if the value is in the HashMap, you can use HashMap#containsValue(java.lang.Object).

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