l

fullu_2.py

@@ -0,0 +1,57 @@
+def append(list1, list2):
+    result = []
+    for item in list1 :
+        result = result + [item]
+    for item in list2 :
+        result = result + [item]
+    return result
+def concat(lists):
+    result = []
+    for sublist in lists:
+        result = append(result, sublist)
+    return result
+
+
+def filter(function, list):
+    result = []
+    for item in list:
+        if function(item):
+            result += [item]
+    return result
+
+
+def length(list):
+    count = 0
+    for _ in list:
+        count += 1
+    return count
+
+
+def map(function, list):
+    result = []
+    for item in list:
+        result += [function(item)]
+    return result
+
+
+def foldl(function, list, initial):
+    accumulator = initial
+    for item in list:
+        accumulator = function(accumulator, item)
+    return accumulator
+
+
+def foldr(function, list, initial):
+    accumulator = initial
+    index = length(list) - 1
+    while index >= 0:
+        accumulator = function(accumulator, list[index])
+        index -= 1
+    return accumulator
+
+
+def reverse(list):
+    result = []
+    for item in list:
+        result = [item] + result
+    return result

u2/list_ops.py

@@ -11,9 +11,11 @@ def concat(lists):
         result = append(result, item)
     return result
 def filter(function, list):
+
     res = []
+    for item in list:
         if function(item) :
-        res = res + item
+            res = res + [item]
     return res
 def length(list) :
     counter = 0
@@ -23,6 +25,20 @@ def length(list) :
 def map(function, list) :
     res = []
     for item in list:
-        res = [function(item)] + res
+        res = res + [function(item)]
     return res
-        
+def foldl(function, list, initial):
+    final = initial
+    for item in list:
+        final = function(final, item)
+    return final
+def foldr(function, list, initial):
+    final = initial
+    for item in reverse(list):
+        final = function(final, item)
+    return final
+def reverse(list):
+    result = []
+    for item in list:
+        result = [item] + result
+    return result