|(DATA)6S|3E6U22|London UK (2022-09)|.0007|10.8|11|1|0|4|4|20220909
I want to extract each value after | and assign each of them to a variable. But as for the third item, I want to extract only "London UK", from the third | to the first
( (without a space before ().
/\|([^)]+)\s
this is the closest I could get, but it catches |3E6U22|London UK, not London UK.
Regex is way too slow (and a bit overkill) for this. What you need is commonly known as splitting a string, and the algorithm to do it is quite simple. Here are some answers where you can find implementations for it:
Splitting a C++ std::string using tokens, e.g. “;”
How do I iterate over the words of a string?
Here's a simple implementation I wrote:
std::vector<std::string> split(std::string s, std::string delim) {
std::vector<std::string> result;
auto last_pos = 0;
for (auto pos = s.find(delim);
pos != std::string::npos;
pos = s.find(delim, last_pos)) {
result.emplace_back(s.begin()+last_pos, s.begin()+pos);
last_pos = pos+delim.size();
}
result.emplace_back(s.begin()+last_pos, s.end());
return result;
}
For the purposes of this answer, here's also an implementation of trim, which we use to remove spaces from the start and end of a string:
std::string& trim_inplace(std::string& s) {
auto not_space = [](char c) {return c != ' ';};
s.erase(s.begin(), std::find_if(s.begin(), s.end(), not_space));
s.erase(std::find_if(s.rbegin(), s.rend(), not_space).base(), s.rbegin().base());
return s;
}
Now that we got those out of the way, here's what you wanna do:
| as a delimiter;Or, in code:
std::string input = "|(DATA)6S|3E6U22|London UK (2022-09)|.0007|10.8|11|1|0|4|4|20220909";
// Split the string using "|" as a delimiter
auto items = split(input, "|");
// Because of the leading "|", the first string will be an empty string. Let's just get rid of it.
items.erase(items.begin());
// If string ends in a closing parenthesis, remove everything between parenthesis
// TBH, it's not clear what are the requirements for removing this
// (seeing as the "(DATA)" part of the first string is not removed as well),
// so this is what I came up with. If your requirements are different,
// you can just change the implementation of the lambda below.
std::transform(items.begin(), items.end(), items.begin(), [](std::string& s) {
if (*s.rbegin() == ')') {
s.erase(s.begin() + s.find_last_of('('), s.end());
}
return s;
});
// Trim spaces at start and end
std::transform(items.begin(), items.end(), items.begin(), trim_inplace);
// Print the result.
for (auto& item : items) {
std::cout << "'" << item << "'\n";
}
Thank you Nick! This is an example of the solution:
#include <string>
#include <regex>
#include <iostream>
int main()
{
std::string newLine = "|(DATA)6S|3E6U22|London UK (2022-09)|.0007|10.8|11|1|0|4|4|20220909";
std::regex reg(R"(\|(.[^(|]*)(?=\||\s\(|$))");
std::sregex_iterator it(newLine.begin(), newLine.end(), reg);
std::sregex_iterator end;
while(it != end)
{
std::smatch m = *it;
std::cout << m.str(1) << std::endl;
++it;
}
return 0;
}
/* RESULT
(DATA)6S
3E6U22
London UK
.0007
10.8
11
1
0
4
4
20220909
*/
I think regex calculations are overwhelming for the case. I'd not prefer it.
Here is simply my two cents.
first character is assumed "|"
and characters in "str"
for i = 1 till null character
if str[i] is not '|'
print str[i]
else
print newline
If you want to store them in a container like 2D array,
hold extra two counter, one of them for 2D array's
first dimension, per word. The other is to start from 0
and end when hit '|' character. Having hit, start the second
counter from zero again.
It would be done by using pointer but more exertion for you, even better using built-in split functions.
