32 lines
746 B
Go
32 lines
746 B
Go
package go_koans
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func aboutMaps() {
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ages := map[string]int{
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"bob": 10,
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"joe": 20,
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"dan": 30,
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}
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age := ages["bob"]
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assert(age == 10) // map syntax is warmly familiar
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age, ok := ages["bob"]
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assert(ok == true) // with a handy multiple-assignment variation
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age, ok = ages["steven"]
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assert(age == 0) // the zero value is used when absent
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assert(ok == false) // though there are better ways to check for presence
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assert(len(ages) == 3) // length is based on keys
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ages["bob"] = 99
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assert(ages["bob"] == 99) // values can be changed for keys
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ages["steven"] = 77
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assert(ages["steven"] == 77) // new ones can be added
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delete(ages, "steven")
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age, ok = ages["steven"]
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assert(ok == false) // key/value pairs can be removed
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}
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