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- [/
- Copyright 2010 Neil Groves
- Distributed under the Boost Software License, Version 1.0.
- (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- /]
- [section:map_keys map_keys]
- [table
- [[Syntax] [Code]]
- [[Pipe] [`rng | boost::adaptors::map_keys`]]
- [[Function] [`boost::adaptors::keys(rng)`]]
- ]
- * [*Precondition:] The `value_type` of the range is an instantiation of `std::pair`.
- * [*Postcondition:] For all elements `x` in the returned range, `x` is the result of `y.first` where `y` is the corresponding element in the original range.
- * [*Range Category:] __single_pass_range__
- * [*Range Return Type:] `boost::select_first_range<decltype(rng)>`
- * [*Returned Range Category:] The range category of `rng`.
- [section:map_keys_example map_keys example]
- [import ../../../test/adaptor_test/map_keys_example.cpp]
- [map_keys_example]
- [endsect]
- This would produce the output:
- ``
- 0,1,2,3,4,5,6,7,8,9,
- ``
- [endsect]
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