A string_view is a C++ class template that is a non-owning reference to a string.
Reference: http://en.cppreference.com/w/cpp/experimental/basic_string_view
Questions tagged [string-view]
138 questions
266
votes
5 answers
How exactly is std::string_view faster than const std::string&?
std::string_view has made it to C++17 and it is widely recommended to use it instead of const std::string&.
One of the reasons is performance.
Can someone explain how exactly std::string_view is/will be faster than const std::string& when used as a…
Patryk
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What is string_view?
string_view was a proposed feature within the C++ Library Fundamentals TS(N3921) added to C++17
As far as i understand it is a type that represent some kind of string "concept" that is a view of any type of container that could store something…
Drax
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Why is there no support for concatenating std::string and std::string_view?
Since C++17, we have std::string_view, a light-weight view into a contiguous sequence of characters that avoids unnecessary copying of data. Instead of having a const std::string& parameter, it is now often recommended to use…
s3rvac
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Why is there no implicit conversion from std::string_view to std::string?
There is an implicit conversion from std::string to std::string_view and it's not considered unsafe, even though this surely may cause a lot of dangling references if programmer is not careful.
On the other hand, there's no implicit conversion from…
GreenScape
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Use of string_view for map lookup
The following code fails to build on recent compilers (g++-5.3, clang++-3.7).
#include
Jean-Michaël Celerier
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How you convert a std::string_view to a const char*?
Compiling with gcc-7.1 with the flag -std=c++17, the following program raises an error:
#include
void foo(const char* cstr) {}
void bar(std::string_view str){
foo(str);
}
The error message is
In function 'void…
Justin Raymond
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When would I pass const& std::string instead of std::string_view?
I understand the motivation for using std::string_view;
it can help avoid unecessary allocations in function arguments.
For example:
The following program will create a std::string from a string literal.
This causes an undesired dynamic…
Trevor Hickey
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How to convert std::string_view to double?
I'm writing a c++ parser for a custom option file for an application. I have a loop that reads lines in the form of option=value from a text file where value must be converted to double. In pseudocode it does the following:
while(not EOF)
…
patatahooligan
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Any gotchas replacing global const char[] with constexpr string_view?
Our team is working with a 10+ years old C++ code base and recently switched to a C++17 compiler. So we are looking for ways to modernize our code. In a conference talk on YouTube I heard the suggestion, to replace const char* global strings with…
PixelSupreme
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Why does std::string_view create a dangling view in a ternary expression?
Consider a method that returns a std::string_view either from a method that returns a const std::string& or from an empty string. To my surprise, writing the method this way results in a dangling string view:
const std::string&…
gexicide
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Is it legal to static_cast a string_view to a string
My question is motivated by this answer on stackoverflow, https://stackoverflow.com/a/48082010/5360439. To quote,
Q: How you convert a std::string_view to a const char*?
A: Simply do a std::string(string_view_object).c_str() to get a guaranteed…
JohnKoch
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Safely convert std::string_view to int (like stoi or atoi)
Is there a safe standard way to convert std::string_view to int?
Since C++11 std::string lets us use stoi to convert to int:
std::string str = "12345";
int i1 = stoi(str); // Works, have i1 = 12345
int i2 = stoi(str.substr(1,2));…
Phil-ZXX
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Is a std::string_view literal guaranteed to be null-terminated?
I know that a trivial std::string_view is not guaranteed to be null-terminated. However, I don't know if a std::string_view literal is guaranteed to be null-terminated.
For example:
#include
using namespace std::literals;
int…
xmllmx
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Should methods returning const std::string& return const std::string_view instead?
Assume we have a simple getter method in a class that returns a const reference to a std::string member:
const std::string& getString() const noexcept { return someString; }
With the advent of std::string_view in C++17, I wonder whether it has any…
andreee
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Why string_view instead of generalized container_view?
I've found string_view from new C++17 standard a bit redundant.
We've got a quite verbose collection of simple mechanisms for passing data to callee, without much overhead and now there is one another which is also specific only to one container…
LookAheadAtYourTypes
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