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https://github.com/k06a/boolinq
Simplest C++ header-only LINQ template library
https://github.com/k06a/boolinq
Last synced: 17 days ago
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Simplest C++ header-only LINQ template library
- Host: GitHub
- URL: https://github.com/k06a/boolinq
- Owner: k06a
- License: mit
- Created: 2012-02-26T09:25:40.000Z (over 12 years ago)
- Default Branch: master
- Last Pushed: 2023-02-05T21:09:34.000Z (almost 2 years ago)
- Last Synced: 2024-07-31T22:49:38.277Z (3 months ago)
- Language: C++
- Homepage:
- Size: 790 KB
- Stars: 622
- Watchers: 29
- Forks: 81
- Open Issues: 15
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# boolinq 3.0
[](https://app.travis-ci.com/github/k06a/boolinq)
[](https://coveralls.io/github/k06a/boolinq?branch=master)
Super tiny C++11 single-file header-only LINQ template library
Just imagine .NET Framework LINQ support for STL/Qt collections :)
Get source code here: **[boolinq.h](/include/boolinq/boolinq.h)**
## Wanna demo?
#### Example with integers
```C++
int src[] = {1,2,3,4,5,6,7,8};
auto dst = from(src).where( [](int a) { return a % 2 == 1; }) // 1,3,5,7
.select([](int a) { return a * 2; }) // 2,6,10,14
.where( [](int a) { return a > 2 && a < 12; }) // 6,10
.toStdVector();
// dst type: std::vector
// dst items: 6,10
```
#### Example with structs
```C++
struct Man {
std::string name;
int age;
};
Man src[] = {
{"Kevin",14},
{"Anton",18},
{"Agata",17},
{"Terra",20},
{"Layer",15},
};
auto dst = from(src).where( [](const Man & man) { return man.age < 18; })
.orderBy([](const Man & man) { return man.age; })
.select( [](const Man & man) { return man.name; })
.toStdVector();
// dst type: std::vector
// dst items: "Kevin", "Layer", "Agata"
```
#### Interesting example
```C++
struct Message {
std::string PhoneA;
std::string PhoneB;
std::string Text;
};
Message messages[] = {
{"Anton","Troll","Hello, friend!"},
{"Denis","Wride","OLOLO"},
{"Anton","Papay","WTF?"},
{"Denis","Maloy","How r u?"},
{"Denis","Wride","Param-pareram!"},
};
int DenisUniqueContactCount =
from(messages).where( [](const Message & msg) { return msg.PhoneA == "Denis"; })
.distinct([](const Message & msg) { return msg.PhoneB; })
.count();
// DenisUniqueContactCount == 2
```
## Test in C++14 using auto
The following test requires C++14 **[GroupByTestComplex.cpp](/include/boolinq/test.GroupByTestComplex.cpp)** It uses auto in order to avoid a very long lambda argument type.
The return type of a function or lambda expression can be deduced by its operand since C++14. The CMake file is changed so that this test runs with C++14.
```C++
TEST(GroupBy, CountTaxes)
{
struct Tax {
std::string name;
int amount_1;
int amount_2;
bool operator ==(const Tax & tax) const {
return name == tax.name
&& amount_1 == tax.amount_1
&& amount_2 == tax.amount_2;
}
};
std::vector taxes = {
{"tax 1", 1, 1},
{"tax 2", 1, 1},
{"tax 1", 2, 2},
{"tax 3", 3, 3},
{"tax 1", 4, 4},
};
Tax ans[] = {
{"tax 1", 7, 7},
{"tax 2", 1, 1},
{"tax 3", 3, 3},
};
auto dst = from(taxes)
.groupBy([](const Tax & a){return a.name;})
.select([](const auto & pair){ // use of auto here needs c++14
return Tax {
pair.first,
pair.second.sum([](const Tax & a){return a.amount_1;}),
pair.second.sum([](const Tax & a){return a.amount_2;})
};
});
CheckRangeEqArray(dst, ans);
}
```
## Containers supported?
- C++: Native arrays, pairs of pointers
- STL: list, stack, queue, vector, deque, set, map, any compatible ....
- Qt: QList, QVector, QSet, QMap.
## Operators supported?
#### Filters and reorders:
- `where(predicate)`, `where_i(predicate)`
- `take(count)`, `takeWhile(predicate)`, `takeWhile_i(predicate)`
- `skip(count)`, `skipWhile(predicate)`, `skipWhile_i(predicate)`
- `orderBy()`, `orderBy(transform)`
- `distinct()`, `distinct(transform)`
- `append(items)`, `prepend(items)`
- `concat(linq)`
- `reverse()`
- `cast()`
#### Transformers:
- `select(transform)`, `select_i(transform)`
- `groupBy(transform)`
- `selectMany(transfom)`
#### Aggregators:
- `all()`, `all(predicate)`
- `any()`, `any(lambda)`
- `sum()`, `sum()`, `sum(lambda)`
- `avg()`, `avg()`, `avg(lambda)`
- `min()`, `min(lambda)`
- `max()`, `max(lambda)`
- `count()`, `count(value)`, `count(predicate)`
- `contains(value)`
- `elementAt(index)`
- `first()`, `first(filter)`, `firstOrDefault()`, `firstOrDefault(filter)`
- `last()`, `last(filter)`, `lastOrDefault()`, `lastOrDefault(filter)`
- `toStdSet()`, `toStdList()`, `toStdDeque()`, `toStdVector()`
#### Bits and Bytes:
- `bytes(ByteDirection?)`
- `unbytes(ByteDirection?)`
- `bits(BitsDirection?, BytesDirection?)`
- `unbits(BitsDirection?, BytesDirection?)`
#### Coming soon:
- gz()
- ungz()
- leftJoin
- rightJoin
- crossJoin
- fullJoin