Added method to do ZIP with array of arrays.

Underscore/USArrayWrapper.h

@@ -58,6 +58,7 @@
 @property (readonly) USArrayWrapper *(^each)(UnderscoreArrayIteratorBlock block);
 @property (readonly) USArrayWrapper *(^map)(UnderscoreArrayMapBlock block);
 @property (readonly) USArrayWrapper *(^zipWith)(NSArray *array, UnderscoreArrayZipWithBlock block);
+@property (readonly) USArrayWrapper *zip;
 
 @property (readonly) USArrayWrapper *(^pluck)(NSString *keyPath);
 

Underscore/USArrayWrapper.m

@@ -243,6 +243,19 @@ - (USArrayWrapper *)shuffle
     };
 }
 
+- (USArrayWrapper *)zip
+{
+    int length = (int)[self.first count];
+    NSMutableArray *finalMutableArray = [NSMutableArray arrayWithCapacity:length * self.array.count];
+    for (NSUInteger index = 0; index < length; index++) {
+        USArrayWrapper *wrapper = self.map(^id (id obj) {
+            return [obj objectAtIndex:index];
+        });
+        [finalMutableArray addObject:wrapper.unwrap];
+    }
+    return [[USArrayWrapper alloc] initWithArray:finalMutableArray];
+}
+
 - (USArrayWrapper *(^)(NSString *))pluck
 {
     return ^USArrayWrapper *(NSString *keyPath) {

Underscore/Underscore+Functional.h

@@ -52,7 +52,7 @@
 + (void (^)(NSArray *array, UnderscoreArrayIteratorBlock block))arrayEach;
 + (NSArray *(^)(NSArray *array, UnderscoreArrayMapBlock block))arrayMap;
 + (NSArray *(^)(NSArray *firstArray, NSArray *secondArray, UnderscoreArrayZipWithBlock block))arrayZipWith;
-
++ (NSArray *(^)(NSArray *))zip;
 + (NSArray *(^)(NSArray *array, NSString *keyPath))pluck;
 
 + (NSArray *(^)(NSArray *array))uniq;

Underscore/Underscore+Functional.m

@@ -142,6 +142,13 @@ @implementation Underscore (Functional)
     };
 }
 
++ (NSArray *(^)(NSArray *))zip
+{
+    return ^(NSArray *array) {
+        return Underscore.array(array).zip.unwrap;
+    };
+}
+
 + (NSArray *(^)(NSArray *, NSString *))pluck
 {
     return ^(NSArray *array, NSString *keyPath) {