So, how would you go about converting
String csv = "11,00,33,66,44,33,22,00,11";
to a hashset in the quickest-most optimized way.
This is for a list of user-ids.
I ran all the answers provided through a test program where each method was called 500,000 times for a bigger CSV string. This test was performed 5 times continously (in case program startup slowed initial method) and I got the following in milliseconds (ms):
Method One Liner-> 6597
Method Split&Iterate-> 6090
Method Tokenizer-> 4306
------------------------------------------------
Method One Liner-> 6321
Method Split&Iterate-> 6012
Method Tokenizer-> 4227
------------------------------------------------
Method One Liner-> 6375
Method Split&Iterate-> 5986
Method Tokenizer-> 4340
------------------------------------------------
Method One Liner-> 6283
Method Split&Iterate-> 5974
Method Tokenizer-> 4302
------------------------------------------------
Method One Liner-> 6343
Method Split&Iterate-> 5920
Method Tokenizer-> 4227
------------------------------------------------
static void method0_oneLiner() {
for (int j = 0; j < TEST_TIMES; j++) {
Set<String> hashSet = new HashSet<String>(Arrays.asList(csv
.split(",")));
}
}
// ———————————————————————————————–
static void method1_splitAndIterate() {
for (int j = 0; j < TEST_TIMES; j++) {
String[] values = csv.split(",");
HashSet<String> hSet = new HashSet<String>(values.length);
for (int i = 0; i < values.length; i++)
hSet.add(values[i]);
}
}
static void method2_tokenizer() {
for (int j = 0; j < TEST_TIMES; j++) {
HashSet<String> hSet = new HashSet<String>();
StringTokenizer st = new StringTokenizer(csv, ",");
while (st.hasMoreTokens())
hSet.add(st.nextToken());
}
}
String[] values = csv.split(",");
Set<String> hashSet = new HashSet<String>(Arrays.asList(values));