Provides fluent interface of LINQ-style query to Objective-C.
This project ports LINQ standard query operators to Objective-C. This is achieved by collection of categories for NSArray and NSDictionary classes.
This library is available through CocoaPods.
Source code of this project is available under the standard MIT license. Please see the license file.
id people = @[
[Person createWithName:@"Adam" withAge:23],
[Person createWithName:@"Alex" withAge:22],
[Person createWithName:@"Andrew" withAge:28],
[Person createWithName:@"Anthony" withAge:19],
[Person createWithName:@"Mark" withAge:30],
[Person createWithName:@"Matt" withAge:47],
[Person createWithName:@"Simon" withAge:33],
[Person createWithName:@"Steve" withAge:55],
];
id result = [[[people linq_where:^BOOL(id item) {
return ([item age] > 21);
}] linq_select:^id(id item) {
return [item name];
}] linq_groupBy:^id(id item) {
return [item substringToIndex:1];
}];
for (id key in [result allKeys]) {
id names = [[result valueForKey:key]
linq_aggregate:^id(id item, id aggregate) {
return [NSString stringWithFormat:@"%@, %@",
aggregate, item];
}];
NSLog(@"%@ : %@", key, names);
}
/*
Output:
A : Adam, Alex, Andrew
M : Mark, Matt
S : Simon, Steve
*/- Aggregation Operations
- Converting Operations
- Filtering Operations
- Generation Operations
- Grouping Operations
- Partitioning Operations
- Projection Operations
- Quantifier Operations
- Set Operations
- Sorting Operations
Performs a custom aggregation operation on the values of a collection.
- (id)linq_aggregate:(id (^)(id item, id aggregate))block;The following example creates a coma-separated string from an array of strings.
NSArray *input = @[@"M", @"A", @"R", @"K"];
NSString *result = [input linq_aggregate:^id(id item, id aggregate) {
return [NSString stringWithFormat:@"%@, %@", aggregate, item];
}];
// Result is: @"M, A, R, K"Calculates the average value of a collection of values.
- (id)linq_avg;Calculates the average value of the attribute specified by the key parameter for all objects in the collection.
- (id)linq_avgForKey:(NSString *)key; Example: Return the average length of strings in the collection.
NSArray *words = @[@"A", @"AB", @"ABC", @"ABCD", @"ABCDE"];
NSNumber *avg_word_length = [words linq_avgForKey:@"length"];
// Result is 3.Counts the elements in a collection, optionally only those elements that satisfy a predicate function.
- (NSUInteger)linq_count:(BOOL (^)(id item))block;Example: Return the number of elements in the collection that are not smaller than 8.
NSArray *numbers = [NSArray linq_from:1 to:10];
NSInteger *count = [numbers linq_count:^BOOL(id item) {
return ([item compare:@8] != NSOrderedAscending);
}];
// Count is 3.Determines the maximum value in a collection.
- (id)linq_max;Calculates the max value of the attribute specified by the key parameter for all objects in a collection.
- (id)linq_maxForKey:(NSString *)key;Determines the minimum value in a collection.
- (id)linq_min;Calculates the min value of the attribute specified by the key parameter for all objects in the collection.
- (id)linq_minForKey:(NSString *)key;Calculates the sum of the values in a collection.
- (id)linq_sum;Calculates the sum of values of the attribute specified by the key parameter for all objects in a collection.
- (id)linq_sumForKey:(NSString *)key;Puts value elements into an NSArray.
- (NSArray *)linq_toArray;Puts value elements into a NSArray which satisfy key condtion.
- (NSArray *)linq_toArrayWhereKey:(BOOL (^)(id item))block;Puts value elements into a NSArray which satisfy value condtion.
- (NSArray *)linq_toArrayWhereValue:(BOOL (^)(id item))block;Puts value elements into a NSArray which satisfy both key and value condtion.
- (NSArray *)linq_toArrayWhereKeyValue:(BOOL (^)(id key, id value))block;Puts elements into an index-key-based NSDictionary.
- (NSDictionary *)linq_toDictionary;Puts elements into a NSDictionary based on a key selector function.
- (NSDictionary *)linq_toDictionaryWithKeyBlock:(id (^)(id item))block;Puts elements into a NSDictionary based on a key and value selector functions.
- (NSDictionary *)linq_toDictionaryWithKeyBlock:(id (^)(id item))keyBlock
valueBlock:(id (^)(id item))valueBlock;Selects values, depending on their ability to be cast to a specified type.
- (instancetype)linq_ofType:(Class)klass;Selects elements which keys can be cast to a specified type.
- (instancetype)linq_ofTypeKey:(Class)klass;Selects elements which values can be cast to a specified type.
- (instancetype)linq_ofTypeValue:(Class)klass;Selects values that are based on a predicate function.
- (instancetype)linq_where:(BOOL (^)(id item))block;Selects values which satisify key-value condition.
- (instancetype)linq_where:(BOOL (^)(id key, id value))block;Selects values which keys satisify condition.
- (instancetype)linq_whereKey:(BOOL (^)(id item))block;Selects values which satisify condition.
- (instancetype)linq_whereValue:(BOOL (^)(id item))block;Returns empty array.
+ (instancetype)linq_empty;Creates array with integers from to.
+ (instancetype)linq_from:(NSInteger)from to:(NSInteger)to;Generates a collection that contains one repeated value.
+ (instancetype)linq_repeat:(id)element count:(NSInteger)count;Returns NSDictionary of groups that share a common attribute defined by selector. Each group is defined as a dictionary entry whose key is a result of a selector and its value is an array of all elements that return the same key, i.e. selector(element) -> key.
{ key <- selector(element), value <- [element : key = selector(element)] }
- (NSDictionary *)linq_groupBy:(id (^)(id item))block;Example:
NSArray *words = @[@"Adam", @"Anthony",
@"Ben", @"Bob",
@"Michael", @"Max", @"Matt",
@"Simon"];
NSDictionary *results = [self.input_words linq_groupBy:^id(id item) {
return [item substringToIndex:1];
}];
// Result is:
// {
// {"A" : @[@"Adam", @"Anthony"]},
// {"B" : @[@"Ben", @"Bob"]},
// {"M" : @[@"Michael", @"Max", @"Matt"]}
// {"S" : @[@"Simon"]}
// }Returns array of NSDictionaries by entering each element
into a NSDictionary whose key is a result of a selector
and its value is an element: { key <- selector(element), value <- element}
- (instancetype)linq_toLookup:(id (^)(id item))block;Helps to filter results of toLookup: method. Returns array of NSDictionaries with the same key.
- (instancetype)linq_lookup:(id)key;Skips elements up to a specified position in a collection.
- (NSArray *)linq_skip:(NSInteger)count;
- (NSDictionary *)linq_skip:(NSInteger)count;Takes elements up to a specified position in a collection.
- (NSArray *)linq_take:(NSInteger)count;
- (NSDictionary *)linq_take:(NSInteger)count;Projects values that are based on a transform function.
- (instancetype)linq_select:(id (^)(id item))block;The example below adds 10 to each element in the collection.
NSArray *result = [[NSArray linq_from:1 to:5] linq_select:^id(id item) {
return [NSNumber numberWithInteger:([item integerValue] + 10)];
}];
// result is @[@11, @12, @13, @14, @15];Projects sequences of values that are based on a transform function and then flattens them into one sequence.
- (instancetype)linq_selectMany:(id (^)(id item))block;This example returns words of each string of the collection.
NSArray *input = @[@"an apple a day", @"the quick brown fox"];
NSArray *result = [input linq_selectMany:^id(id item) {
return [item componentsSeparatedByString:@" "];
}];
// result is @[@"an", @"apple", @"a", @"day",
// @"the", @"quick", @"brown", @"fox"]
//Determines whether all the elements in a sequence satisfy a condition.
- (BOOL)linq_all:(BOOL (^)(id item))block;
- (BOOL)linq_all:(BOOL (^)(id key, id value))block;Determines whether any elements in a sequence satisfy a condition.
- (BOOL)linq_any:(BOOL (^)(id item))block;
- (BOOL)linq_any:(BOOL (^)(id key, id value))block;Removes duplicate values from a collection.
- (instancetype)linq_distinct;Returns the collection without the elements that appear in a second collection.
- (instancetype)linq_except:(NSArray *)other;
- (instancetype)linq_except:(NSDictionary *)other;Returns the set intersection, which means elements that appear in each of two collections.
- (instancetype)linq_intersect:(NSArray *)other;
- (instancetype)linq_intersect:(NSDictionary *)other;Returns the set union, which means unique elements that appear in either of two collections.
- (NSArray *)linq_union:(NSArray *)other;Merges to dictionaries by returning the set union of unique elements which keys appear in either of two dictionaries.
- (NSDictionary *)linq_merge:(NSDictionary *)other;Sorts values in ascending order.
- (instancetype)linq_orderByAscending;Sorts values in descending order.
- (instancetype)linq_orderByDescending;Sorts elements of a collection depending on an element's key.
- (instancetype)linq_orderByKey:(NSString *)key ascending:(BOOL)ascending;Reverses the order of the elements in a collection.
- (instancetype)linq_reverse;- Fork it.
- Create your feature branch (
git checkout -b new-feature). - Commit your changes (
git commit -am 'Added new-feature'). - Push to the branch (
git push origin new-feature). - Create new Pull Request.