C++ 检查字符串是否作为向量中的元素存在
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Checking if a string is present as an element in a vector
提问by user620189
What's the most efficient way to check whether an stl vector of strings contains a specific string?
检查字符串的 stl 向量是否包含特定字符串的最有效方法是什么？
回答by Mark B
The obvious yet possibly too-slow solution is std::find(vec.begin(), vec.end(), your_string);
明显但可能太慢的解决方案是 std::find(vec.begin(), vec.end(), your_string);
If your vector isn't changing much, sort it first, then use binary_search, lower_bound, upper_bound, or equal_range. If your vector changes a lot, consider using a set/multiset(or if needed map/multimap) instead.
如果您的载体没有太大变化，但排序第一，然后使用binary_search，lower_bound，upper_bound，或equal_range。如果您的向量变化很大，请考虑使用set/ multiset（或如果需要map/ multimap）。
Depending on your needs a hash (unordered_set) might be appropriate as well, but it's more different from your initial container choice than normal ordered containers, and not supplied prior to C++0x (you can get it from boost easily).
根据您的需要，散列 ( unordered_set) 也可能是合适的，但它与您的初始容器选择比普通有序容器更不同，并且在 C++0x 之前不提供（您可以轻松地从 boost 获得它）。
回答by quamrana
Use std::findto find the target string. This is a linear search, so beware searching large vectors.
使用std::find找到目标字符串。这是一个线性搜索，所以要小心搜索大向量。
To find out if the vector contains the target or not, use:
要确定向量是否包含目标，请使用：
bool isPresent = (std::find(vec.begin(), vec.end(), target) != vec.end());
回答by davidhigh
Here is a C++11 alternative:
这是一个 C++11 替代方案：
#include<functional>
#include<vector>
#include<string>
std::vector<std::string> v;
bool elementFound = std::any_of(v.begin(), v.end(), [](std::string const& s) {return s=="string-to-search";});
Feel free to adjust the lambda function to what you want, e.g.
随意将 lambda 函数调整为您想要的，例如
[](std::string const& s) {return s.size()>3;}
回答by jmccarthy
vector<string> v;
vector<string>::iterator it;
it = std::find(v.begin(), v.end(), "stringToFind");
回答by Mahesh
Use std::find to find the string.
使用 std::find 查找字符串。
std::find(stringVector.begin(), stringVector.end(), "specificStringToFind") ;
