从 C++ 中的 std::string 中删除空格
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Remove spaces from std::string in C++
提问by Steve Hanov
What is the preferred way to remove spaces from a string in C++? I could loop through all the characters and build a new string, but is there a better way?
在 C++ 中从字符串中删除空格的首选方法是什么？我可以遍历所有字符并构建一个新字符串，但是有更好的方法吗？
回答by Matt Price
The best thing to do is to use the algorithm remove_ifand isspace:
最好的办法是使用算法remove_if和isspace：
remove_if(str.begin(), str.end(), isspace);
Now the algorithm itself can't change the container(only modify the values), so it actually shuffles the values around and returns a pointer to where the end now should be. So we have to call string::erase to actually modify the length of the container:
现在算法本身不能改变容器（只能修改值），所以它实际上对值进行了混洗并返回一个指向现在结束位置的指针。所以我们必须调用 string::erase 来实际修改容器的长度：
str.erase(remove_if(str.begin(), str.end(), isspace), str.end());
We should also note that remove_if will make at most one copy of the data. Here is a sample implementation:
我们还应该注意到 remove_if 最多只能复制一份数据。这是一个示例实现：
template<typename T, typename P>
T remove_if(T beg, T end, P pred)
{
T dest = beg;
for (T itr = beg;itr != end; ++itr)
if (!pred(*itr))
*(dest++) = *itr;
return dest;
}
回答by Arno
std::string::iterator end_pos = std::remove(str.begin(), str.end(), ' ');
str.erase(end_pos, str.end());
回答by rupello
回答by Nemanja Trifunovic
Can you use Boost String Algo? http://www.boost.org/doc/libs/1_35_0/doc/html/string_algo/usage.html#id1290573
您可以使用 Boost 字符串算法吗？http://www.boost.org/doc/libs/1_35_0/doc/html/string_algo/usage.html#id1290573
erase_all(str, " ");
回答by Roman
For trimming, use boost string algorithms:
对于修剪，使用提升字符串算法：
#include <boost/algorithm/string.hpp>
using namespace std;
using namespace boost;
// ...
string str1(" hello world! ");
trim(str1); // str1 == "hello world!"
回答by user2281802
You can use this solution for removing a char:
您可以使用此解决方案来删除字符：
#include <algorithm>
#include <string>
using namespace std;
str.erase(remove(str.begin(), str.end(), char_to_remove), str.end());
回答by ddacot
Hi, you can do something like that. This function deletes all spaces.
你好，你可以这样做。此函数删除所有空格。
string delSpaces(string &str)
{
str.erase(std::remove(str.begin(), str.end(), ' '), str.end());
return str;
}
I made another function, that deletes all unnecessary spaces.
我做了另一个功能，删除所有不必要的空间。
string delUnnecessary(string &str)
{
int size = str.length();
for(int j = 0; j<=size; j++)
{
for(int i = 0; i <=j; i++)
{
if(str[i] == ' ' && str[i+1] == ' ')
{
str.erase(str.begin() + i);
}
else if(str[0]== ' ')
{
str.erase(str.begin());
}
else if(str[i] == 'string replaceinString(std::string str, std::string tofind, std::string toreplace)
{
size_t position = 0;
for ( position = str.find(tofind); position != std::string::npos; position = str.find(tofind,position) )
{
str.replace(position ,1, toreplace);
}
return(str);
}
' && str[i-1]== ' ')
{
str.erase(str.end() - 1);
}
}
}
return str;
}
回答by SudoBash
string replace = replaceinString(thisstring, " ", "%20");
string replace2 = replaceinString(thisstring, " ", "-");
string replace3 = replaceinString(thisstring, " ", "+");
use it:
用它：
#define REMOVE_SPACES(x) x.erase(std::remove(x.begin(), x.end(), ' '), x.end())
回答by Volomike
If you want to do this with an easy macro, here's one:
如果你想用一个简单的宏来做到这一点，这里有一个：
std::string sName = " Example Name ";
REMOVE_SPACES(sName);
printf("%s",sName.c_str()); // requires #include <stdio.h>
This assumes you have done #include <string>of course.
这#include <string>当然假设您已经完成了。
Call it like so:
像这样称呼它：
##代码##回答by RaGa__M
I used the below work around for long - not sure about its complexity.
我长期使用以下工作 - 不确定它的复杂性。
s.erase(std::unique(s.begin(),s.end(),[](char s,char f){return (f==' '||s==' ');}),s.end());
s.erase(std::unique(s.begin(),s.end(),[](char s,char f){return (f==' '||s==' ');}),s.end());
when you wanna remove character ' 'and some for example -use
当你想删除字符' '和一些例如-使用
s.erase(std::unique(s.begin(),s.end(),[](char s,char f){return ((f==' '||s==' ')||(f=='-'||s=='-'));}),s.end());
s.erase(std::unique(s.begin(),s.end(),[](char s,char f){return ((f==' '||s==' ')||(f=='-'||s=='-'));}),s.end());
likewise just increase the ||if number of characters you wanna remove is not 1
同样，||如果您要删除的字符数不是 1 ，则只需增加
but as mentioned by others the erase remove idiom also seems fine.
但正如其他人所提到的，擦除删除习语似乎也不错。
