std::remove, std::remove_if

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Example

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main: () = {
    str1: std::string = ("Text with some   spaces");

    noSpaceEnd:= std::remove(str1.begin(), str1.end(), ' ');

    // The spaces are removed from the string only logically.
    // Note, when we use view, the original string is still not shrunk:
    std::println("{} size: {}", std::string_view(str1.begin(), noSpaceEnd), str1.size());

    _ = str1.erase(noSpaceEnd, str1.end());

    // The spaces are removed from the string physically.
    std::println("{} size: {}", str1, str1.size());

    str2: std::string = ("Text\n with\tsome \t  whitespaces\n\n");
    _ = str2.erase(std::remove_if(str2.begin(),
                                  str2.end(),
                                  :(x: int) std::isspace(x)),
                   str2.end());
    std::println("{}", str2);

    nums: std::vector = (
        :std::complex<double>=(2, 2),
        :std::complex<double>=(1, 3),
        :std::complex<double>=(4, 8));
    _ = nums.erase(std::remove(nums.begin(), nums.end(), std::complex<double>(1, 3)),
                   nums.end());
    assert(
           nums.size() == 2
        && nums[0] == std::complex<double>(2, 2)
        && nums[1] == std::complex<double>(4, 8));
}

Output

Textwithsomespaces size: 23
Textwithsomespaces size: 18
Textwithsomewhitespaces