Working with filter and map functions

farhanjaved47 · farhanjaved47 · commit 9f6535a28acc · 2019-12-30T16:56:38.000+05:00
diff --git a/Python3StandardLibrary/BuiltIn_Part2.py b/Python3StandardLibrary/BuiltIn_Part2.py
@@ -0,0 +1,66 @@
+"""
+Farhan Javed
+farhan.javed47@gmail.com
+12/30/2019
+Part 2 of built in functions in the Python standard library
+"""
+
+
+def filterFunc(x):
+    if x % 2:
+        return True
+    return False
+
+
+def filterFunc2(x):
+    if x.isupper():
+        return False
+    return True
+
+
+def squareFunc(x):
+    return pow(x, 2)
+
+
+def toGrade(x):
+    if x >= 90:
+        return 'A'
+    elif x >= 80:
+        return 'B'
+    elif x >= 70:
+        return 'C'
+    elif x >= 60:
+        return 'D'
+    elif x >= 50:
+        return 'E'
+    return 'F'
+
+
+def main():
+    nums = (1, 8, 45, 11, 221, 57, 72, 89, 92)
+    chars = 'abCDEFghIJKlMNopQRstuvWXyz'
+    grades = (81, 89, 52, 12, 65, 99, 72, 25, 44, 33)
+
+    # TODO : use filter to remove even numbers from a list
+    odds = list(filter(filterFunc, nums))
+    print(sorted(odds))
+    odds_alt = [filterFunc(x) for x in nums]
+    print(sorted(odds_alt))  # generate a list of booleans using list comprehension
+
+    # TODO : use filter on non-numeric sequences
+    lowers = list(filter(filterFunc2, chars))
+    print(lowers)
+
+    # TODO : use map to create a new sequence of values after applying a given function to each item
+    squares = list(map(squareFunc, nums))
+    print(sorted(squares))
+    squares_alt = [pow(i, 2) for i in nums]
+    print(sorted(squares_alt))  # can use list comprehension to achieve the same..
+
+    # TODO :  use sorted and map to convert marks into alphabetical grades
+    grades = sorted(grades)
+    letter_grades = list(map(toGrade, grades))
+    print(letter_grades)
+
+
+if __name__ == '__main__': main()
