diff --git a/CONTRIBUTERS b/CONTRIBUTERS
deleted file mode 100644
index 27f9ec5..0000000
--- a/CONTRIBUTERS
+++ /dev/null
@@ -1,2 +0,0 @@
-- brennerm <xam.rennerb@gmail.com>
-- agumonkey
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
new file mode 100644
index 0000000..de493f1
--- /dev/null
+++ b/CONTRIBUTORS
@@ -0,0 +1,16 @@
+- brennerm <xam.rennerb@gmail.com>
+- agumonkey
+- obeleh
+- Prooffreader
+- cgopalan (cgopalan.github.io)
+- anabalica (ana-balica.github.io)
+- dharmit (github.com/dharmit)
+- shyboynccu (github.com/shyboynccu)
+- illuz
+- tutoringsteve
+- Kzinglzy
+- waveform80 (github.com/waveform80)
+- thatneat (github.com/thatneat)
+- bruno314 (github.com/bruno314)
+- rickhau
+- oztalha (github.com/oztalha)
diff --git a/README.md b/README.md
index 64c68f6..fe0478c 100644
--- a/README.md
+++ b/README.md
@@ -4,8 +4,14 @@ Creating a knowledge base of unpopular Python built-in features to save a lot of
 ## Contribute
 Feel free to use the PyTrickBase.txt as a starting point.
 
-1. Pull request
-Send a pull request with your PyTrick, containing example code and a documentation one-liner. Be sure to add yourself to the contributers.
+1. Pull request:
 
-2. Issue comment
-Add your Python snippet and your documentation as a comment on Issue#1. I will take care of adding your PyTrick and you as a contributer.
+   Send a pull request with your PyTrick, containing example code and a documentation one-liner. Be sure to add yourself to the contributors.
+
+2. Issue comment:
+
+   Add your Python snippet and your documentation as a comment on Issue#1. I will take care of adding your PyTrick and you as a contributor.
+
+## Contact
+1. message me at [@__brennerm](https://twitter.com/__brennerm)
+2. send an email to xam.rennerb@gmail.com
diff --git a/andorassignment.py b/andorassignment.py
deleted file mode 100755
index de60714..0000000
--- a/andorassignment.py
+++ /dev/null
@@ -1,6 +0,0 @@
-#! /usr/bin/env python3
-"""conditional assignment with following structure
-<condition> and <true_result> or <false_result>
-"""
-a = 1
-print(a < 0 and 'negative' or 'positive')
diff --git a/argumentunpacking.py b/argumentunpacking.py
index 0039d29..78c86ef 100755
--- a/argumentunpacking.py
+++ b/argumentunpacking.py
@@ -1,10 +1,10 @@
 #! /usr/bin/env python3
 """simple tuple and dictionary unpacking"""
-def sum(a, b):
-    return a + b
-    
+def product(a, b):
+    return a * b
+
 argument_tuple = (1, 1)
 argument_dict = {'a': 1, 'b': 1}
 
-print(sum(*argument_tuple))
-print(sum(**argument_dict))
\ No newline at end of file
+print(product(*argument_tuple))
+print(product(**argument_dict))
diff --git a/cacheproperty.py b/cacheproperty.py
new file mode 100644
index 0000000..562fc27
--- /dev/null
+++ b/cacheproperty.py
@@ -0,0 +1,29 @@
+class PropertyCache:
+    """ a decorator to cache property
+    """
+
+    def __init__(self, func):
+        self.func = func
+
+    def __get__(self, obj, cls):
+        if not obj:
+            return self
+        value = self.func(obj)
+        setattr(obj, self.func.__name__, value)
+        return value
+        
+
+class Foo:
+    def __init__(self):
+        self._property_to_be_cached = 'result'
+
+    @PropertyCache
+    def property_to_be_cached(self):
+        print('compute')
+        return self._property_to_be_cached
+    
+test = Foo()
+
+print(test.property_to_be_cached)
+print(test.property_to_be_cached)
+
diff --git a/calculator.py b/calculator.py
new file mode 100755
index 0000000..882e2b2
--- /dev/null
+++ b/calculator.py
@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+"""
+This program lets you create a simple command line calculator without using
+the 'if..else' construct. It uses built-in 'operator' module to accomplish the
+same
+
+Created with help of an answer on stackoverflow. Don't have the exact link.
+"""
+
+import operator
+ops = {
+    "+": operator.add,
+    "-": operator.sub,
+    "/": operator.truediv,
+    "*": operator.mul
+}
+
+x = input("Enter an operator [OPTIONS: +, -, *, /]: ")
+y = int(input("Enter number: "))
+z = int(input("Enter number: "))
+
+print (ops[x](y, z))
diff --git a/concatenatestrings.py b/concatenatestrings.py
new file mode 100755
index 0000000..fac8d55
--- /dev/null
+++ b/concatenatestrings.py
@@ -0,0 +1,7 @@
+#! /usr/bin/env python3
+"""Concatenate long strings elegantly 
+across line breaks in code"""
+
+my_long_text = ("We are no longer the knights who say Ni! "
+                "We are now the knights who say ekki-ekki-"
+                "ekki-p'tang-zoom-boing-z'nourrwringmm!")
diff --git a/conditionalfunctioncall.py b/conditionalfunctioncall.py
index 8564fd3..dc8c81f 100755
--- a/conditionalfunctioncall.py
+++ b/conditionalfunctioncall.py
@@ -1,10 +1,10 @@
 #! /usr/bin/env python3
 """calling different functions with same arguments based on condition"""
-def sum(a, b):
-    return a + b
-    
+def product(a, b):
+    return a * b
+
 def subtract(a, b):
     return a - b
-    
+
 b = True
-print((sum if b else subtract)(1, 1))
\ No newline at end of file
+print((product if b else subtract)(1, 1))
diff --git a/controlwhitespaces.py b/controlwhitespaces.py
new file mode 100755
index 0000000..9fc9e94
--- /dev/null
+++ b/controlwhitespaces.py
@@ -0,0 +1,19 @@
+#! /usr/bin/env python3
+"""control the whitespaces in string"""
+
+s = 'The Little Price'
+
+# justify string to be at least width wide
+# by adding whitespaces
+width = 20
+s1 = s.ljust(width)
+s2 = s.rjust(width)
+s3 = s.center(width)
+print(s1)   # 'The Little Price    '
+print(s2)   # '    The Little Price'
+print(s3)   # '  The Little Price  '
+
+# strip whitespaces in two sides of string
+print(s3.lstrip())  # 'The Little Price  '
+print(s3.rstrip())  # '  The Little Price'
+print(s3.strip())   # 'The Little Price'
diff --git a/copylist.py b/copylist.py
new file mode 100755
index 0000000..2328759
--- /dev/null
+++ b/copylist.py
@@ -0,0 +1,22 @@
+#! /usr/bin/env python3
+"""a fast way to make a shallow copy of a list"""
+
+a = [1, 2, 3, 4, 5]
+print(a[:])
+
+"""using the list.copy() method (python3 only)"""
+
+a = [1, 2, 3, 4, 5]
+
+print(a.copy())
+
+
+"""copy nested lists using copy.deepcopy"""
+
+from copy import deepcopy
+
+l = [[1, 2], [3, 4]]
+
+l2 = deepcopy(l)
+print(l2)
+
diff --git a/dictsortbyvalue.py b/dictsortbyvalue.py
new file mode 100755
index 0000000..16c5b29
--- /dev/null
+++ b/dictsortbyvalue.py
@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+""" Sort a dictionary by its values with the built-in sorted() function and a 'key' argument. """
+ 
+d = {'apple': 10, 'orange': 20, 'banana': 5, 'rotten tomato': 1}
+print (sorted(d.items(), key = lambda x: x[1]))
+
+
+""" Sort using operator.itemgetter as the sort key instead of a lambda"""
+
+
+from operator import itemgetter
+
+
+print(sorted(d.items(), key=itemgetter(1)))
+
+
+"""Sort dict keys by value"""
+
+
+print(sorted(d, key=d.get))
diff --git a/dictswapkeysvalues.py b/dictswapkeysvalues.py
new file mode 100755
index 0000000..73d2e9d
--- /dev/null
+++ b/dictswapkeysvalues.py
@@ -0,0 +1,7 @@
+#! /usr/bin/env python3
+"""Swaps keys and values in a dict"""
+
+_dict = {"one": 1, "two": 2}
+# make sure all of dict's values are unique
+assert len(_dict) == len(set(_dict.values()))
+reversed_dict = {v: k for k, v in _dict.items()}
\ No newline at end of file
diff --git a/listcompnestedfor.py b/listcompnestedfor.py
new file mode 100644
index 0000000..4e94b41
--- /dev/null
+++ b/listcompnestedfor.py
@@ -0,0 +1,16 @@
+#! /usr/bin/env python3
+"""flattening nested lists of depth 2 within a single list comprehension with
+multiple for loops"""
+
+l = [
+    [1, 2, 3],
+    [4, 5, 6],
+    [7, 8],
+    [9]
+    ]
+
+print([
+    j
+    for i in l
+    for j in i
+    ])
diff --git a/loopoverlappingdicts.py b/loopoverlappingdicts.py
new file mode 100755
index 0000000..ec9d93c
--- /dev/null
+++ b/loopoverlappingdicts.py
@@ -0,0 +1,8 @@
+#! /usr/bin/env python3
+"""loop over dicts that share (some) keys"""
+
+dctA = {'a': 1, 'b': 2, 'c': 3}
+dctB = {'b': 4, 'c': 5, 'd': 6}
+
+for ky in set(dctA) & set(dctB):
+    print(ky)
diff --git a/maxsplit.py b/maxsplit.py
new file mode 100755
index 0000000..6c60b3b
--- /dev/null
+++ b/maxsplit.py
@@ -0,0 +1,11 @@
+#! /usr/bin/env python3
+"""split a string max times"""
+string = "a_b_c"
+print(string.split("_", 1))
+
+
+"""use maxsplit with  arbitrary whitespace"""
+
+s = "foo    bar   foobar foo"
+
+print(s.split(None, 2))
diff --git a/namedformatting.py b/namedformatting.py
index 7924089..042538a 100755
--- a/namedformatting.py
+++ b/namedformatting.py
@@ -2,4 +2,14 @@
 """easy string formatting using dicts"""
 
 d = {'name': 'Jeff', 'age': 24}
-print("My name is %(name)s and I'm %(age)i years old." % d)
\ No newline at end of file
+print("My name is %(name)s and I'm %(age)i years old." % d)
+
+"""for .format, use this method"""
+
+d = {'name': 'Jeff', 'age': 24}
+print("My name is {name} and I'm {age} years old.".format(**d))
+
+"""dict string formatting"""
+c = {'email': 'jeff@usr.com', 'phone': '919-123-4567'}
+print('My name is {0[name]}, my email is {1[email]} and my phone number is {1[phone]}'.format(d, c))
+
diff --git a/removeduplicatefromlist.py b/removeduplicatefromlist.py
new file mode 100755
index 0000000..6286854
--- /dev/null
+++ b/removeduplicatefromlist.py
@@ -0,0 +1,16 @@
+#! /usr/bin/env python3
+"""remove duplicate items from list. note: does not preserve the original list order"""
+
+items = [2, 2, 3, 3, 1]
+
+newitems2 = list(set(items))
+print(newitems2)
+
+"""remove dups and keep order"""
+
+from collections import OrderedDict
+
+items = ["foo", "bar", "bar", "foo"]
+
+print(list(OrderedDict.fromkeys(items).keys()))
+
diff --git a/reverselist.py b/reverselist.py
index 4a0016c..0fedc4e 100755
--- a/reverselist.py
+++ b/reverselist.py
@@ -2,3 +2,7 @@
 """reverting list with special case of slice step param"""
 a = [5, 4, 3, 2, 1]
 print(a[::-1])
+
+"""iterating over list contents in reverse efficiently."""
+for ele reversed(a):
+  print(ele)
diff --git a/setglobalvariables.py b/setglobalvariables.py
new file mode 100755
index 0000000..b80fb14
--- /dev/null
+++ b/setglobalvariables.py
@@ -0,0 +1,6 @@
+#! /usr/bin/env python3
+"""set global variables from dict"""
+
+d = {'a': 1, 'b': 'var2', 'c': [1, 2, 3]}
+globals().update(d)
+print(a, b, c)
diff --git a/setoperators.py b/setoperators.py
index 80a1431..18825f2 100755
--- a/setoperators.py
+++ b/setoperators.py
@@ -17,4 +17,27 @@
 print(a ^ b)
 
 # Union
-print(a | b)
\ No newline at end of file
+print(a | b)
+
+"""using methods instead of operators which take any iterable as a second arg"""
+
+a = {'a', 'b', 'c', 'd'}
+b = {'c', 'd', 'e', 'f'}
+c = {'a', 'c'}
+
+print(a.intersection(["b"]))
+
+print(a.difference(["foo"]))
+
+print(a.symmetric_difference(["a", "b", "e"]))
+
+print(a.issuperset(["b", "c"]))
+
+print(a.issubset(["a", "b", "c", "d", "e", "f"]))
+
+print(a.isdisjoint(["y", 'z']))
+
+print(a.union(["foo", "bar"]))
+
+a.intersection_update(["a", "c", "z"])
+print(a)
diff --git a/socketmsghandling.py b/socketmsghandling.py
new file mode 100644
index 0000000..151e9ec
--- /dev/null
+++ b/socketmsghandling.py
@@ -0,0 +1,19 @@
+import socket
+import functools
+
+s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+conn = s.connect(('localhost', 80))
+msgs = []
+
+# normal way
+#while True:
+#    msg = coon.recv(1024)
+#    if recv:
+#        msgs.append(msg)
+#    else:  # when no msg come, break
+#         break
+
+# hack way with iter and functools.partial
+# this circle will auto break when msg is empty ''
+for msg in iter(functools.partial(conn.recv, 1024), b''):
+    msgs.append(msg)
\ No newline at end of file
diff --git a/switch.py b/switch.py
new file mode 100755
index 0000000..babf9be
--- /dev/null
+++ b/switch.py
@@ -0,0 +1,8 @@
+#! /usr/bin/env python3
+"""Analogue of switch statement"""
+a = {
+    True: 1,
+    False: -1,
+    None: 0
+}
+print(a.get(False, 0))
diff --git a/transpose.py b/transpose.py
new file mode 100644
index 0000000..f4d0f82
--- /dev/null
+++ b/transpose.py
@@ -0,0 +1,6 @@
+#! /usr/bin/env python3
+"""transpose 2d array [[a,b], [c,d], [e,f]] -> [[a,c,e], [b,d,f]]"""
+
+original = [['a','b'], ['c','d'], ['e','f']]
+transposed = zip (*original)
+print (list(transposed))
\ No newline at end of file
diff --git a/tryelse.py b/tryelse.py
new file mode 100644
index 0000000..ea378b0
--- /dev/null
+++ b/tryelse.py
@@ -0,0 +1,11 @@
+""" You can have an 'else' clause with try/except. 
+    It gets excecuted if no exception is raised.
+    This allows you to put less happy-path code in the 'try' block so you can be 
+    more sure of where a caught exception came from."""
+
+try:
+    1 + 1
+except TypeError:
+    print("Oh no! An exception was raised.")
+else:
+    print("Oh good, no exceptions were raised.")
diff --git a/whileelse.py b/whileelse.py
new file mode 100755
index 0000000..57812e2
--- /dev/null
+++ b/whileelse.py
@@ -0,0 +1,12 @@
+""" You can have an else clause with a while. Works like for-else. 
+    When break is encountered, it exits the loop without executing else. """
+
+i = 5
+
+while i > 1:
+  print("Whil-ing away!")
+  i -= 1
+  if i == 3:
+    break
+else:
+  print("Finished up!")