# @return a list of strings, [s1, s2]
def letterCombinations(self, digits):
    if '' == digits: return []
    kvmaps = {
        '2': 'abc',
        '3': 'def',
        '4': 'ghi',
        '5': 'jkl',
        '6': 'mno',
        '7': 'pqrs',
        '8': 'tuv',
        '9': 'wxyz'
    }
    return reduce(lambda acc, digit: [x + y for x in acc for y in kvmaps[digit]], digits, [''])

primes=[]
products=[]

def prime(num):
    if num > 1:
        for i in range(2,num):
            if (num % i) == 0:
                return False
        else:
            primes.append(num)
            return True

for n in range(30,1000):
    if len(primes) >= 20:
        break;
    else:
        prime(n)

for previous, current in zip(primes[::2], primes[1::2]):
    products.append(previous * current)
    
print (products)

def hex_to_rgb(hex):
  return tuple(int(hex[i:i+2], 16) for i in (0, 2, 4))

hex_to_rgb('FFA501') # (255, 165, 1)

bytes_data = b'Hello, World!'
string_data = bytes_data.decode('utf-8')
print("String:", string_data)

mydict = {'carl':40, 'alan':2, 'bob':1, 'danny':0}

# How to sort a dict by value Python 3>
sort = {key:value for key, value in sorted(mydict.items(), key=lambda kv: (kv[1], kv[0]))}
print(sort)

# How to sort a dict by key Python 3>
sort = {key:mydict[key] for key in sorted(mydict.keys())}
print(sort)

# importing the modules
import os
import shutil

# getting the current working directory
src_dir = os.getcwd()

# printing current directory
print(src_dir) 

# copying the files
shutil.copyfile('test.txt', 'test.txt.copy2') #copy src to dst

# printing the list of new files
print(os.listdir())