CODEWITHSUNDEEP
c++c++20fmt
NoSenseEtAl
NoSenseEtAl

Reputation: 30058

Format range with fmt without enclosing [] brackets

I want to print a range of values with , separator but without [] using fmt library.

If I try to print out some range like this

std::vector v {8,4,7,2};
std::cout  << fmt::format("{}",v) <<"\n";

the output is

[8, 4, 7, 2]

But I actually want the output to be

8, 4, 7, 2

How can I do this?

One approach I've found is to do the following

std::cout  << fmt::format("{}",fmt::join(v,", ")) <<"\n";

which does work. However, it's verbose, and it makes 2 calls to fmt, which I would like to avoid. Is this possible?

demo

Also, due to performance and readability reasons I am not interested in removing [] from the string produced by fmt.

Upvotes: 1

Views: 1881

Answers (1)

ShadowRanger
ShadowRanger

Reputation: 155487

The shorter code is to use fmt to do the printing directly, rather than just using it to format, then passing the result to normal cout the iostream way:

fmt::print("{}\n", fmt::join(v, ", ")); // Optionally, I believe you can use the literals to make the format string compile-type checked, "{}\n"_format

The format string incorporates the newline as well, and print does both the formatting and printing, so it's markedly shorter/less complex than:

std::cout << fmt::format("{}", fmt::join(v, ", ")) << "\n";

Upvotes: 5

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