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Task/Sorting-algorithms-Radix-sort/Python/sorting-algorithms-radix-sort.py

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+#python2.6 <
+from math import log
+
+def getDigit(num, base, digit_num):
+    # pulls the selected digit
+    return (num // base ** digit_num) % base
+
+def makeBlanks(size):
+    # create a list of empty lists to hold the split by digit
+    return [ [] for i in range(size) ]
+
+def split(a_list, base, digit_num):
+    buckets = makeBlanks(base)
+    for num in a_list:
+        # append the number to the list selected by the digit
+        buckets[getDigit(num, base, digit_num)].append(num)
+    return buckets
+
+# concatenate the lists back in order for the next step
+def merge(a_list):
+    new_list = []
+    for sublist in a_list:
+       new_list.extend(sublist)
+    return new_list
+
+def maxAbs(a_list):
+    # largest abs value element of a list
+    return max(abs(num) for num in a_list)
+
+def split_by_sign(a_list):
+    # splits values by sign - negative values go to the first bucket,
+    # non-negative ones into the second
+    buckets = [[], []]
+    for num in a_list:
+        if num < 0:
+            buckets[0].append(num)
+        else:
+            buckets[1].append(num)
+    return buckets
+
+def radixSort(a_list, base):
+    # there are as many passes as there are digits in the longest number
+    passes = int(log(maxAbs(a_list), base) + 1)
+    new_list = list(a_list)
+    for digit_num in range(passes):
+        new_list = merge(split(new_list, base, digit_num))
+    return merge(split_by_sign(new_list))