Created
April 17, 2018 14:20
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[Language Processing 100 Essentials] #62: Iterate to count the number of artists in specified area
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package main | |
import ( | |
"flag" | |
"fmt" | |
"os" | |
"github.com/go-redis/redis" | |
) | |
// TODO: improve O(n) implementation... | |
// https://stackoverflow.com/questions/17193176/searching-in-values-of-a-redis-db | |
func main() { | |
var area string | |
flag.StringVar(&area, "area", "", "specify the area") | |
flag.Parse() | |
client, err := newRedisClient() | |
if err != nil { | |
fmt.Println(err) | |
os.Exit(1) | |
} | |
keys, err := client.Keys("*").Result() | |
if err != nil { | |
fmt.Println(err) | |
os.Exit(1) | |
} | |
count := 0 | |
for _, key := range keys { | |
val, err := client.Get(key).Result() | |
if err != nil { | |
fmt.Println(err) | |
os.Exit(1) | |
} | |
if val != area { | |
continue | |
} | |
count++ | |
} | |
fmt.Printf("found %d keys\n", count) | |
} | |
func newRedisClient() (*redis.Client, error) { | |
client := redis.NewClient(&redis.Options{ | |
Addr: "127.0.0.1:6379", | |
Password: "", | |
DB: 0, | |
}) | |
pong, err := client.Ping().Result() | |
if err != nil { | |
return nil, fmt.Errorf("could not connect to redis\n %s", err) | |
} | |
fmt.Println(pong, err) | |
return client, nil | |
} |
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package main | |
import ( | |
"fmt" | |
"testing" | |
"github.com/go-test/deep" | |
) | |
var countArtistsTests = []struct { | |
name string | |
area string | |
want int | |
}{ | |
{ | |
name: "should count the number of artists correctly", | |
area: "Minneapolis–Saint Paul", | |
// actual count is 9 but that artist name is duplicated and overwritten by the one in another area. | |
want: 8, | |
}, | |
{ | |
name: "should return zero", | |
area: "null", | |
want: 0, | |
}, | |
} | |
func TestGetKeyVal(t *testing.T) { | |
for _, testcase := range countArtistsTests { | |
t.Log(testcase.name) | |
client, err := newRedisClient() | |
if err != nil { | |
t.Error(err) | |
} | |
keys, err := client.Keys("*").Result() | |
if err != nil { | |
t.Error(err) | |
} | |
count := 0 | |
for _, key := range keys { | |
val, err := client.Get(key).Result() | |
if err != nil { | |
t.Error(err) | |
} | |
if val != testcase.area { | |
continue | |
} | |
fmt.Println(key) | |
count++ | |
} | |
if diff := deep.Equal(count, testcase.want); diff != nil { | |
t.Error(diff) | |
} | |
} | |
} |
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