How to find a value in a list of tuple in C++?

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I have a list of tuple written in c++. each tuple consists of two elements. I want to find a value in the second element of the tuples in the list. how can I find it?
the list is as follow:

list<std::tuple<int, int> > d;

i want it find for example the number "2" in d.item[2].

What I have tried:

i found some references about finding a value in a list of tuples . but, those tuples had consisted on just one element. but, my case has two elements in each tuple.

Posted 18-Apr-17 7:29am

Member 11807654

Updated 18-Apr-17 10:20am

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Richard MacCutchan 18-Apr-17 15:02pm

You need to go through the list looking for the value you want to find.

Maciej Los 18-Apr-17 16:01pm

i found some references about - use that logic!

Philippe Mori 18-Apr-17 18:55pm

If you want to do such search, then your design is somewhat suspicious. Using a map where the key would be the second item of your pair and the value the first one would be more sensible. If you really want to search such item, then you can specify a predicate when doing your search. In any case, reading the documentation might be a good idea.

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Maciej Los · Accepted Answer · 2017-04-18T10:20:00

Solution 1

Check the documentation: std::tuple - cppreference.com[^]

If i understand you well...
All you need to do is to loop through the elements on the list[^], then to use std::get() function.

Think of it!

Tip:
d(0) - returns the first element on the list
std::get<1>(d(0)) - returns second element of tuple of first element on the list

Posted 18-Apr-17 10:20am

Maciej Los

Updated 18-Apr-17 10:21am

v2

Comments

Member 11807654 19-Apr-17 1:58am

thanks

Maciej Los 19-Apr-17 4:16am

You're very welcome