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I need to create a function called random_grades that returns a list consisting of 40 random letters from (A-F).
This is the code so far.. but i dont know how to make the output letters and not numbers...
import random
random_grades = [random.randint(5,10) for i in range (40)]
A = 10
B = 9
C = 8
D = 7
E = 6
F = 5
print(random_grades)
random.choices does it directly:
random.seed(0) # make it reproducible
random.choices('ABCDEF', k=40)
give:
['F', 'E', 'C', 'B', 'D', 'C', 'E', 'B', 'C', 'D', 'F', 'D', 'B', 'E', 'D', 'B', 'F', 'F', 'E', 'F', 'B', 'E', 'F', 'E', 'C', 'A', 'C', 'D', 'F', 'F', 'C', 'F', 'B', 'E', 'D', 'A', 'E', 'C', 'E', 'E']
This works because a string is an iterable of characters...
You can use a map index -> grade aka an array, and the random variable is the index.
import random
grades = ['A','B','C','D','E','F']
random_grades_indexes = [random.randint(0,len(grades)-1) for i in range (40)]
random_grades = [ grades[i] for i in random_grades_indexes]
print(random_grades)
Which prints
['D', 'A', 'A', 'B', 'D', 'E', 'A', 'E', 'D', 'E', 'B', 'A', 'A', 'B', 'D', 'B', 'E', 'A', 'F', 'B', 'B', 'D', 'C', 'F', 'E', 'B', 'A', 'B', 'C', 'E', 'E', 'C', 'F', 'D', 'A', 'F', 'B', 'C', 'B', 'E']
As a proof that you will get a uniform distribution, we can create an histogram of the grades running 1000 grades.
import random
def count_elements(seq) -> dict:
hist = {}
for i in seq:
hist[i] = hist.get(i, 0) + 1
return hist
grades = ['A','B','C','D','E','F']
random_grades_indexes = [random.randint(0,len(grades)-1) for i in range (1000)]
random_grades = [ grades[i] for i in random_grades_indexes]
dist = count_elements(random_grades)
print(dist)
Which gives
{'C': 175, 'F': 153, 'A': 153, 'E': 174, 'D': 174, 'B': 171}
I want to create all possible permutations for an array in which each element can only occur once, with constraints on the element array index position.
ID = ["A","B","C","D","E","F","G","H","I","J"]
I want to create all possible permutations of the original_array, however the positions of each element are restricted to index positions given by:
ID = ["A","B","C","D","E","F","G","H","I","J"]
Index_Options=[]
for i in range(len(ID)):
List1=[]
distance=3
value = i - distance
for j in range((int(distance)*2)):
if value < 0 or value > len(ID):
print("Disregard") #Outside acceptable distance range
else:
List1.append(value)
value=value+1
Index_Options.append(List1)
print(Index_Options)
#Index_Options gives the possible index positions for each element. ie "A" can occur in only index positions 0,1,2, "B" can occur in only index positions 0,1,2,3 ect.
I'm just struggling on how to then use this information to create all the output permutations.
Any help would be appreciated
You can use a recursive generator function to build the combinations. Instead of generating all possible permutations from ID and then filtering based on Index_Options, it is much more efficient to produce a cartesian product of ID by directly traversing Index_Options:
ID = ["A","B","C","D","E","F","G","H","I","J"]
def combos(d, c = [], s = []):
if not d:
yield c
else:
for i in filter(lambda x:x not in s and x < len(ID), d[0]):
yield from combos(d[1:], c=c+[ID[i]], s=s+[i])
print(list(combos(Index_Options)))
Output (first ten combinations produced):
[['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J'], ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'I'], ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'I', 'H', 'J'], ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'I', 'J', 'H'], ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'J', 'H', 'I'], ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'J', 'I', 'H'], ['A', 'B', 'C', 'D', 'E', 'F', 'H', 'G', 'I', 'J'], ['A', 'B', 'C', 'D', 'E', 'F', 'H', 'G', 'J', 'I'], ['A', 'B', 'C', 'D', 'E', 'F', 'H', 'I', 'G', 'J'], ['A', 'B', 'C', 'D', 'E', 'F', 'H', 'I', 'J', 'G']]
You can use itertools.permutations to create all the possible permutations and then create new list with a check if all the letters are in the correct position
permutations = [p for p in itertools.permutations(ID, len(ID)) if all(i in Index_Options[ID.index(x)] for i, x in enumerate(p))]
I have a list of lists containing unique strings and I want to produce an arbitrary number of different ways of sorting it. The list might look like the following:
list = [[a], [b,c], [d], [e,f,g]]
The order of the lists need to be the same but I want to shuffle the ordering within a list and then have them in a single list, e.g
list1 = [a,b,c,d,e,f,g]
list2 = [a,c,b,d,f,e,g]
...
...
listN = [a,c,b,d,f,g,e]
What is a good pythonic way of achieving this? I'm on python 2.7.
from itertools import permutations, product
L = [['a'], ['b','c'], ['d'], ['e', 'f', 'g']]
for l in product(*map(lambda l: permutations(l), L)):
print([item for s in l for item in s])
produces:
['a', 'b', 'c', 'd', 'e', 'f', 'g']
['a', 'b', 'c', 'd', 'e', 'g', 'f']
['a', 'b', 'c', 'd', 'f', 'e', 'g']
['a', 'b', 'c', 'd', 'f', 'g', 'e']
['a', 'b', 'c', 'd', 'g', 'e', 'f']
['a', 'b', 'c', 'd', 'g', 'f', 'e']
['a', 'c', 'b', 'd', 'e', 'f', 'g']
['a', 'c', 'b', 'd', 'e', 'g', 'f']
['a', 'c', 'b', 'd', 'f', 'e', 'g']
['a', 'c', 'b', 'd', 'f', 'g', 'e']
['a', 'c', 'b', 'd', 'g', 'e', 'f']
['a', 'c', 'b', 'd', 'g', 'f', 'e']
You can do this by taking the Cartesian product of the permutations of the sub-lists, and then flattening the resulting nested tuples.
from itertools import permutations, product, chain
lst = [['a'], ['b', 'c'], ['d'], ['e', 'f', 'g']]
for t in product(*[permutations(u) for u in lst]):
print([*chain.from_iterable(t)])
output
['a', 'b', 'c', 'd', 'e', 'f', 'g']
['a', 'b', 'c', 'd', 'e', 'g', 'f']
['a', 'b', 'c', 'd', 'f', 'e', 'g']
['a', 'b', 'c', 'd', 'f', 'g', 'e']
['a', 'b', 'c', 'd', 'g', 'e', 'f']
['a', 'b', 'c', 'd', 'g', 'f', 'e']
['a', 'c', 'b', 'd', 'e', 'f', 'g']
['a', 'c', 'b', 'd', 'e', 'g', 'f']
['a', 'c', 'b', 'd', 'f', 'e', 'g']
['a', 'c', 'b', 'd', 'f', 'g', 'e']
['a', 'c', 'b', 'd', 'g', 'e', 'f']
['a', 'c', 'b', 'd', 'g', 'f', 'e']
If you need to do this in Python 2, you can replace the print line with this:
print list(chain.from_iterable(t))
Here's a more compact version, inspired by ewcz's answer:
for t in product(*map(permutations, lst)):
print list(chain.from_iterable(t))
This might not be the most elegant solution, but I think it does what you want
from itertools import permutations
import numpy as np
def fac(n):
if n<=1:
return 1
else:
return n * fac(n-1)
lists = [['a'], ['b','c'], ['d'], ['e','f','g']]
combined = [[]]
for perm in [permutations(l,r=len(l)) for l in lists]:
expanded = []
for e in list(perm):
expanded += [list(l) + list(e) for l in combined]
combined = expanded
## check length
print np.prod(map(fac,map(len,lists))), len(combined)
print '\n'.join(map(str,combined))
You can flatten the list then simply generate its permutations:
from itertools import chain, permutations
li = [['a'], ['b','c'], ['d'], ['e','f','g']]
flattened = list(chain.from_iterable(li))
for perm in permutations(flattened, r=len(flattened)):
print(perm)
>> ('a', 'b', 'c', 'd', 'e', 'f', 'g')
('a', 'b', 'c', 'd', 'e', 'g', 'f')
('a', 'b', 'c', 'd', 'f', 'e', 'g')
('a', 'b', 'c', 'd', 'f', 'g', 'e')
('a', 'b', 'c', 'd', 'g', 'e', 'f')
('a', 'b', 'c', 'd', 'g', 'f', 'e')
('a', 'b', 'c', 'e', 'd', 'f', 'g')
('a', 'b', 'c', 'e', 'd', 'g', 'f')
('a', 'b', 'c', 'e', 'f', 'd', 'g')
...
...
...
from itertools import chain, permutations
your_list = [[a], [b,c], [d], [e,f,g]]
flattened = chain.from_iterable(your_list)
perms = permutations(flattened)
for perm in perms:
print perm
References:
permutations in Python 2
chain in Python 2
I'm beginner to programming and I'm new here, so hello!
I'm having a problem with nodes order in networkX.
This code:
letters = []
G = nx.Graph()
for i in range(nodesNum):
letter = ascii_lowercase[i]
letters.append(letter)
print letters
G.add_nodes_from(letters)
print "G.nodes = ", (G.nodes())
returns this:
['a']
['a', 'b']
['a', 'b', 'c']
['a', 'b', 'c', 'd']
['a', 'b', 'c', 'd', 'e']
['a', 'b', 'c', 'd', 'e', 'f']
['a', 'b', 'c', 'd', 'e', 'f', 'g']
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']
G.nodes = ['a', 'c', 'b', 'e', 'd', 'g', 'f', 'i', 'h', 'j']
While I would like to have it in normal (alphabetical) order.
Could anyone tell me what am I doing wrong?
The order is important to me, as later I'm asking user to tell me where the edges are.
Thanks in advance!
You can sort the nodes on output like this
print "G.nodes = ", sorted(G.nodes())
or similarly you can sort the edges like
print "G.edges = ", sorted(G.edges())
Aric's solution would do fine if you want to use this for printing only. However if you are going to use adjacent matrix for calculations and you want consistent matrices in different runs, you should do:
letters = []
G = nx.OrderedGraph()
for i in range(10):
letter = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'][i]
letters.append(letter)
print (letters)
G.add_nodes_from(letters)
print ("G.nodes = ", (G.nodes()))
which returns
['a']
['a', 'b']
['a', 'b', 'c']
['a', 'b', 'c', 'd']
['a', 'b', 'c', 'd', 'e']
['a', 'b', 'c', 'd', 'e', 'f']
['a', 'b', 'c', 'd', 'e', 'f', 'g']
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']
G.nodes = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']
Currently working on a transposition problem. What I have so far is that a user enters a message and that message is encrypted into a list, like below:
['BC', 'DE', 'DE', 'DA', 'FD', 'DD', 'BE', 'FE', 'DA', 'EA', 'FE', 'BC']
What I have for the next stage of the cipher is putting this into a table with a key inputted from the user. So if the user enters 'CODE' it outputs this:
2: Enter the keyword for final encryption: code
C O D E
['B', 'C', 'D', 'E']
['D', 'E', 'D', 'A']
['F', 'D', 'D', 'D']
['B', 'E', 'F', 'E']
['D', 'A', 'E', 'A']
['F', 'E', 'B', 'C']
The next stage is to take each value of each column and print the values corresponding to its alphabetical column. So my expected output would be:
C D E O
['B', 'D', 'E', 'C']
['D', 'D', 'A', 'E']
['F', 'D', 'D', 'D']
['B', 'F', 'E', 'E']
['D', 'E', 'A', 'A']
['F', 'B', 'C', 'E']
The problem I'm having is trying to know how to put each of the values in their corresponding column and printing them.
Here's what I have so far:
def encodeFinalCipher():
matrix2 = []
# Convert keyword to upper case
key = list(keyword.upper())
# Convert firstEncryption to a string
firstEncryptionString = ''.join(str(x) for x in firstEncryption)
# Print the first table that will show the firstEncryption and the keyword above it
keywordList = list(firstEncryptionString)
for x in range(0,len(keywordList),len(keyword)):
matrix2.append(list(keywordList[x:x+len(keyword)]))
# Print the un-ordered matrix to the screen
print (' %s' % ' '.join(map(str, key)))
for letters in matrix2:
print (letters)
unOrderedMatrix = [[matrix2[i][j] for i in range(len(matrix2))] for j in range(len(matrix2[0]))]
for index, item in enumerate (unOrderedMatrix):
print("\n",index, item)
index = sorted(key)
print(index)
I get the output of the sorted key:
['A', 'K', 'M', 'R']
What I would like to know is how can this sorted key be applied to the values they represent? I know I can get the first column by doing this:
print(unOrderedMatrix[0])
Which gets me the list of the first column.
Any help would be much appreciated. Complete beginner on Python
msg = ['BC', 'DE', 'DE', 'DA', 'FD', 'DD', 'BE', 'FE', 'DA', 'EA', 'FE', 'BC', '12']
key = 'CODE'
# 'flatten' the message
msg = ''.join(msg)
key_length = len(key)
#create a dictionary with the letters of the key as the keys
#use a slice to create the values
columns = {k:msg[i::key_length] for i, k in enumerate(key)}
print columns
# sort the columns on the key letters
columns = sorted(columns.items())
print columns
# separate the key from the columnar data
header, data = zip(*columns)
print header
# transpose and print
for thing in zip(*data):
print thing
>>>
{'C': 'BDFBDF1', 'E': 'EADEAC', 'D': 'DDDFEB', 'O': 'CEDEAE2'}
[('C', 'BDFBDF1'), ('D', 'DDDFEB'), ('E', 'EADEAC'), ('O', 'CEDEAE2')]
('C', 'D', 'E', 'O')
('B', 'D', 'E', 'C')
('D', 'D', 'A', 'E')
('F', 'D', 'D', 'D')
('B', 'F', 'E', 'E')
('D', 'E', 'A', 'A')
('F', 'B', 'C', 'E')
>>>
code = raw_input("Enter the keyword for final encryption:")
user_input = ['BC', 'DE', 'DE', 'DA', 'FD', 'DD', 'BE', 'FE', 'DA', 'EA', 'FE', 'BC']
user_input = ''.join(user_input)
matrix = [user_input[i:i+len(code)] for i in range(0, len(user_input), len(code))]
matrix.insert(0, code)
result = sorted([[matrix[j][ind] for j in range(len(matrix))] for ind in range(len(code)) ], key= lambda i:i[0])
for row in [[each[ind] for each in result] for ind in range(len(result[0]))]:
print row
Print row results as:
Enter the keyword for final encryption:CODE
['C', 'D', 'E', 'O']
['B', 'D', 'E', 'C']
['D', 'D', 'A', 'E']
['F', 'D', 'D', 'D']
['B', 'F', 'E', 'E']
['D', 'E', 'A', 'A']
['F', 'B', 'C', 'E']
Here is something to get you started (you may want to separate the loop one-liner to smaller bits):
# define data
data = [['B', 'C', 'D', 'E'], ['D', 'E', 'D', 'A'], ['F', 'D', 'D', 'D'], ['B', 'E', 'F', 'E'], ['D', 'A', 'E', 'A'], ['F', 'E', 'B', 'C']]
# choose code word
code = 'code'
# add original locations to code word [(0, c), (1, o), (2, d), (3, e))]
# and sort them alphabetically!
code_with_locations = list(sorted(enumerate(code)))
print code_with_locations # [(0, 'c'), (2, 'd'), (3, 'e'), (1, 'o')]
# re-organize data according to new indexing
for index in range(len(data)):
# check if code is shorter than list in current index,
# or the other way around, don't exceed either list
max_substitutions = min(map(len, [code_with_locations, data[index]]))
# create a new list according to new indices
new_list = []
for i in range(max_substitutions):
current_index = code_with_locations[i][0]
new_list.append(data[index][current_index])
# replace old list with new list
data[index] = new_list
print data
Output for 'code' would be:
[['B', 'D', 'E', 'C'],
['D', 'D', 'A', 'E'],
['F', 'D', 'D', 'D'],
['B', 'F', 'E', 'E'],
['D', 'E', 'A', 'A'],
['F', 'B', 'C', 'E']]
With help from itertools
from pprint import pprint
from itertools import chain, izip_longest
def grouper(iterable, n, fillvalue=None):
"Collect data into fixed-length chunks or blocks"
# grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx
args = [iter(iterable)] * n
return izip_longest(fillvalue=fillvalue, *args)
z = ['BC', 'DE', 'DE', 'DA', 'FD', 'DD', 'BE', 'FE', 'DA', 'EA', 'FE', 'BC']
input = 'CODE'
pprint([[b for (a, b) in sorted(zip(input, x))]
for x in grouper(chain.from_iterable(z), len(input))])
[['B', 'D', 'E', 'C'],
['D', 'D', 'A', 'E'],
['F', 'D', 'D', 'D'],
['B', 'F', 'E', 'E'],
['D', 'E', 'A', 'A'],
['F', 'B', 'C', 'E']]