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Carol (Nichols || Goulding) 2016-09-26 22:42:37 -04:00
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src/ch08-03-hash-maps.md
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@ -121,6 +121,13 @@ This will print:
### Updating a Hash Map
Since each key can only have one value, when we want to change the data in a
hash map, we have to decide how to handle the case when a key already has a
value assigned. We could choose to replace the old value with the new value. We
could choose to keep the old value and ignore the new value, and only add the
new value if the key *doesn't* already have a value. Or we could change the
existing value. Let's look at how to do each of these!
#### Overwriting a Value
If we insert a key and a value, then insert that key with a different value, the value associated with that key will be replaced. Even though this code calls `insert` twice, the hash map will only contain one key/value pair, since we're inserting with the key `1` both times: