redis:set数据类型与操作

rfcvd

　　set是集合。我们可以向一个集合中“插入”，“删除”元素，也可以计算两个集合的“交集”，“并集”，及“作差”。如：
　　假设有集合A，B。
　　其中，A={1,2,3,4,5},B={4,5,6,7,8}。
　　那么，
　　交集：inter（A，B）= {4,5}
　　并集：union（A， B）= {1,2,3,4,5,6,7,8}
　　差集：diff（A，B）= {1,2,3}，即属于集合A，但不属于集合B的元素
　　


　　set的是通过hash table实现的，所以添加、删除和查找的复杂度都是O(1)。hash table会随着添加或者删除自动的调整大小。需要注意的是调整hash table大小时候需要同步(获取写锁)会阻塞其他读写操作，可能不久后就会改用跳表(skip list)来实现，跳表已经在sorted set中使用了。（引自：http://hb.qq.com/a/20111001/000022.htm）
　　


　　关于set数据类型的操作详见：http://redis.readthedocs.org/en/2.4/set.html
　　下面结合redis c++接口，了解一下这些基本操作。

#include "redisclient.h"
#include "tests/functions.h"
#include <iostream>
#include <boost/date_time.hpp>
#define OUT(x) std::cout<<#x<<&quot; = &quot;<<x<<std::endl;
boost::shared_ptr<redis::client> init_non_cluster_client();
void output_set(redis::client::string_set & sset);
void test_set(redis::client & c);
int main(int argv, char* argc[])
{
boost::shared_ptr<redis::client> shared_c;
shared_c = init_non_cluster_client();
redis::client& c = *shared_c;
test_set(c);
return 0;
}
void test_set(redis::client & c)
{
test(&quot;test redis set type.&quot;);
test(&quot;sadd&quot;);
{
std::vector<std::string> vals;
for(size_t i=0; i<10; ++i) {
char ch = (char)('A'+i);
std::string tmp =&quot;&quot;;
tmp += ch;
vals.push_back(tmp);
}
std::vector<std::string>::iterator it;
c.sadd(&quot;set_a&quot;, vals.begin(), vals.end());
}
test(&quot;smembers&quot;);
{
redis::client::string_set out;
OUT(c.smembers(&quot;set_a&quot;, out));
output_set( out );
}
test(&quot;srem&quot;);
{
c.srem(&quot;set_a&quot;, &quot;A&quot;);
redis::client::string_set out;
OUT(c.smembers(&quot;set_a&quot;, out));
output_set( out );
}
test(&quot;sismember&quot;);
{
OUT( c.sismember(&quot;set_a&quot;, &quot;A&quot;) );
OUT( c.sismember(&quot;set_a&quot;, &quot;B&quot;) );
}
test(&quot;scard&quot;);
{
OUT( c.scard(&quot;set_a&quot;) );
}
test(&quot;smove&quot;);
{
c.smove(&quot;set_a&quot;, &quot;set_b&quot;, &quot;B&quot;);
redis::client::string_set out;
OUT(c.smembers(&quot;set_a&quot;, out));
output_set(out);
out.clear();
OUT(c.smembers(&quot;set_b&quot;, out));
output_set( out );
}
test(&quot;spop&quot;);
{
OUT( c.scard(&quot;set_a&quot;) );
OUT( c.spop(&quot;set_a&quot;) );
OUT( c.scard(&quot;set_a&quot;) );
}
test(&quot;srandmember&quot;);
{
OUT( c.srandmember(&quot;set_a&quot;) );
}
test(&quot;sinter&quot;);
{
c.sadd(&quot;set_b&quot;, &quot;C&quot;);
c.sadd(&quot;set_b&quot;, &quot;F&quot;);
redis::client::string_vector keys;
keys.push_back(&quot;set_a&quot;);
keys.push_back(&quot;set_b&quot;);
redis::client::string_set out;
c.smembers(&quot;set_a&quot;, out);
std::cout<<&quot;set a:  *******************&quot;<<std::endl;
output_set(out);
out.clear();
c.smembers(&quot;set_b&quot;, out);
std::cout<<&quot;set b:  *******************&quot;<<std::endl;
output_set(out);
c.sinter(keys, out);
output_set(out);
}
test(&quot;sinterstore&quot;);
{
redis::client::string_vector keys;
redis::client::string_set out;
keys.push_back(&quot;set_a&quot;);
keys.push_back(&quot;set_b&quot;);
c.sinterstore(&quot;set_c&quot;, keys);
c.smembers(&quot;set_c&quot;, out);
output_set(out);
}
test(&quot;sunion & sunionstore&quot;);
{
redis::client::string_vector keys;
redis::client::string_set out;
keys.push_back(&quot;set_a&quot;);
keys.push_back(&quot;set_b&quot;);
c.sunion(keys, out);
output_set(out);
out.clear();
c.sunionstore(&quot;set_d&quot;, keys);
c.smembers(&quot;set_d&quot;, out);
std::cout<<&quot;set d: ****************&quot;<<std::endl;
output_set(out);
}
test(&quot;sdiff * sdiffstore&quot;);
{
redis::client::string_vector keys;
redis::client::string_set out;
keys.push_back(&quot;set_a&quot;);
keys.push_back(&quot;set_b&quot;);
c.sdiff(keys, out);
output_set(out);
out.clear();
c.sdiffstore(&quot;set_e&quot;, keys);
c.smembers(&quot;set_e&quot;, out);
std::cout<<&quot;set e: ****************&quot;<<std::endl;
output_set(out);
}
}
void output_set(redis::client::string_set & sset)
{
size_t size = sset.size();
OUT(size);
redis::client::string_set::iterator it;
for(it=sset.begin(); it!=sset.end(); ++it) {
OUT(*it);
}
}


　　



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