u2

u2/list_ops.py

@@ -0,0 +1,45 @@
+def append(list1, list2):
+    result = []
+    for x in list1:
+        result = result + [x]
+    for x in list2:
+        result = result + [x]
+
+def concat(lists):
+    result = []
+    for list in lists:
+        append(result, list)
+    return result
+
+def filter(function, list):
+    result = []
+    for x in list:
+        if function(x):
+            result = result + [x]
+    return result
+
+def length(list):
+    lng = 0
+    for i in list:
+        lng += 1
+    return lng
+
+def map(function, list):
+    result = []
+    for x in list:
+        if function(x) not in result:
+            result = result + [x]
+    return result
+
+def foldl(function, list, initial):
+    acc = initial
+    for x in list:
+        acc = function(acc, x)
+    return acc
+
+def foldr(function, list, initial):
+    return foldl(function, reverse(list), initial)
+
+def reverse(list):
+    result = list[::-1]
+    return result