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Using Python, how to print output string as -> aaa3bb2c1ddddd5 when Input string is aaabbcddddd

Using Python, how to print output string as -> aaa3bb2c1ddddd5 when Input string is aaabbcddddd
I want to concatenate actual character value and number of times a character is repeated in a string
def mycode(myString):
lenstr = len(myString)
print('length of string is '+str(lenstr));
for ele in myString:
count=0
for character in myString:
if character == ele:
count = count+1
totalstr = ele+str(count)
return totalstr

If the string is always sorted and grouped together like that, then you can use a collections.Counter to do it.
from collections import Counter
inp = "aaabbcddddd"
counter = Counter(inp)
out = "".join(k * v + str(v) for k,v in counter.items())
Or in one line:
print(''.join(k * v + str(v) for k,v in Counter(inp).items()))
Output:
aaa3bb2c1ddddd5
Or you can do it manually:
inp = "aaabbcddddd"
last = inp[0]
out = inp[0]
count = 1
for i in inp[1:]:
if i == last:
count += 1
else:
out += str(count)
count = 1
last = i
out += i
out += str(count)
print(out)

Here is a one line solution using a regex replacement with callback:
inp = "aaabbcddddd"
output = re.sub(r'((\w)\2*)', lambda m: m.group(1) + str(len(m.group(1))), inp)
print(output) # aaa3bb2c1ddddd5

Another one-liner:
import itertools
test = 'aaabbcddddd'
out = ''.join(f"{(g := ''.join(ig))}{len(g)}" for _, ig in itertools.groupby(test))
assert out == 'aaa3bb2c1ddddd5'

def char_counter_string(string):
prev_char = None
char_counter = 0
output = ''
for char_index in range(len(string)+1):
if char_index == len(string):
output += str(char_counter)
break
if string[char_index] != prev_char and prev_char is not None:
output += str(char_counter)
char_counter = 0
output += string[char_index]
char_counter += 1
prev_char = string[char_index]
return output
if __name__ == '__main__':
print(char_counter_string('aaabbcddddd'))

you can do like..
Code:
Time Complexity: O(n)
input_string="aaabbcddddd"
res=""
count=1
for i in range(1, len(input_string)):
if input_string[i] == input_string[i-1]:
count += 1
else:
res+=input_string[i-1]*count + str(count)
count = 1
res+=input_string[-1]*count + str(count)
print(res) #aaa3bb2c1ddddd5

Here's another way, ...
Full disclosure: ... as long as the run of characters is 10 or less, it will work. I.e., if there are 11 of anything in row, this won't work (the count will be wrong).
It's just a function wrapping a reduce.
from functools import reduce
def char_rep_count(in_string):
return reduce(
lambda acc, inp:
(acc[:-1]+inp+str(int(acc[-1])+1))
if (inp==acc[-2])
else (acc+inp+"1"),
in_string[1:],
in_string[0]+"1"
)
And here's some sample output:
print(char_rep_count("aaabbcdddd"))
aaa3bb2c1dddd4

I think this fulfils the brief and is also very fast:
s = 'aaabbcddddd'
def mycode(myString):
if myString:
count = 1
rs = [prev := myString[0]]
for c in myString[1:]:
if c != prev:
rs.append(f'{count}')
count = 1
else:
count += 1
rs.append(prev := c)
rs.append(f'{count}')
return ''.join(rs)
return myString

Python Vigenere Cipher Encrypt method not encrypting properly

The encrypt method in my program is not encrypting correctly. I thought I figured out why using debug mode; it's because it reads the spaces between words as something it has to encrypt. So I tried typing a message without spaces but it still didn't come out correctly.
I figure the issue is the if statement with the key. I tried commenting lines out, changing statements, changing the if statement to a for loop, but it still isn't correct.
def main():
vig_square = create_vig_square()
message = input("Enter a multi-word message with punctuation: ")
input_key = input("Enter a single word key with no punctuation: ")
msg = message.lower()
key = input_key.lower()
coded_msg = encrypt(msg, key, vig_square)
print("The encoded message is: ",coded_msg)
print("The decoded message is: ", msg)
def encrypt(msg,key,vig_square):
coded_msg = ""
key_inc = 0
for i in range(len(msg)):
msg_char = msg[i]
if key_inc == len(key)-1:
key_inc = 0
key_char = key[key_inc]
if msg_char.isalpha() and key_char.isalpha():
row_index = get_row_index(key_char,vig_square)
col_index = get_col_index(msg_char,vig_square)
coded_msg = coded_msg+vig_square[row_index][col_index]
else:
coded_msg = coded_msg + " "
key_inc = key_inc+1
return coded_msg
def get_col_index(msg_char, vig_square):
column_index = ord(msg_char) - 97
return column_index
def get_row_index(key_char, vig_square):
row_index = ord(key_char) - 97
return row_index
def create_vig_square():
vig_square = list()
for row in range(26):
next_row = list()
chr_code = ord('a') + row
for col in range(26):
letter = chr(chr_code)
next_row.append(letter)
chr_code = chr_code + 1
if chr_code > 122:
chr_code = ord('a')
vig_square.append(next_row)
return vig_square
main()
This example was given to us:
Enter a multi-word message with punctuation: The eagle has landed.
Enter a single word key with no punctuation: LINKED
The encoded message is: epr oejwm ukw olvqoh.
The decoded message is: the eagle has landed.
But my encoded message comes out as:
epr iloyo sif plvqoh

You have two errors:
First, you don't use all characters in the key. Change the following line:
if key_inc == len(key)-1:
key_inc = 0
to
if key_inc == len(key):
key_inc = 0
Second, you move the key pointer even if you process a non-alpha character in the message (e.g. spaces). Do it only if you encode a character, i.e. make the following change:
if msg_char.isalpha() and key_char.isalpha():
...
key_inc = key_inc+1 # Move this line here
else:
...

Replace all spaces in a string with underscores

How would I replace the spaces in a string with underscores without using the replace function. I was told to also use a accumulation string with some type of loop
string = input("Enter a string")
i = 0
acc = ""
for char in string:
if char == " ":
acc = string + "_"
print(acc)

Try this,
string = input("Enter a string")
i = 0
acc = ""
newlist = [] #create a new list which will be the output
strlist = list(string) #create a list of each character in the input string
for char in strlist:
if char == " ":
newlist.append('_')
newlist.append(char)
acc = ''.join(newlist)
print(acc)

Your code should to be :
string = input("Enter a string")
i = 0
acc = ""
for char in string:
if char == " ":
acc += "_"
else:
acc += char
print(acc)
Try it if without replace.
string = input("Enter a string")
res = ''.join(["_" if i == " " else i for i in string])
print(res)
Another method:
string = input("Enter a string")
res = "_".join(string.split(" "))
print(res)

Your code isn't too far off. You can use an accumulation string like this:
string = input("Enter a string")
acc = ""
for char in string:
if char == " ":
char = "_"
acc += char
print(acc)

If you are allowed to use split, then
s = 'Your string with spaces'
s_ = ''
for word in s.split():
s_ += '_' + word
s_[1:] # 'Your_string_with_spaces'
Otherwise, instead of words, concatenate characters with '_' instead of ' ':
s_ = ''
for char in s:
if char == ' ':
s_ += '_'
else:
s_ += char

List prints square brackets in python 2.7

import sys
import string
import re
keywords = []
task = "*"
while task not in "ed":
task = raw_input("Encrypt or Decrypt: \nType ‘e’ to Encrypt\nType ‘d’ to Decrypt\n").lower()
keyword = "*"
keyphrase = "*"
while not(re.match('[a-z ]+$',keyword)):
keyword = raw_input("enter your first keyword:-").lower()
while not(re.match('[a-z ]+$',keyphrase)):
keyphrase = raw_input("enter a key phrase:-").lower()
loop = 0
repeated_keyword = ""
if len(keyword) < len(keyphrase):
while len(repeated_keyword) < len(keyphrase):
repeated_keyword = repeated_keyword + keyword[loop]
loop += 1
if loop >= len(keyword):
loop = 0
elif len(keyword) == len(keyphrase):
repeated_keyword = keyword
last_charecter_in_keyword = keyword[-1]
elif len(keyword) > len(keyphrase):
repeated_keyword = keyword
last_charecter_in_keyword = keyword[-1]
while len(repeated_keyword) > len(keyphrase):
repeated_keyword = repeated_keyword[:-1]
repeated_keyword_letter_positions = []
keyphrase_letter_positions = []
for character in repeated_keyword:
position_of_char_in_repeated_keyword = (string.ascii_lowercase + " ").find(character) +1
repeated_keyword_letter_positions.append(position_of_char_in_repeated_keyword)
for character in keyphrase:
position_of_char_in_keyphrase = (string.ascii_lowercase + " ").find(character)
keyphrase_letter_positions.append(position_of_char_in_keyphrase)
if task == "e":
final_positions_of_letters = [a + b for a, b in zip(keyphrase_letter_positions,repeated_keyword_letter_positions)]
elif task == "d":
final_positions_of_letters = [a - b for a, b in zip(keyphrase_letter_positions,repeated_keyword_letter_positions)]
new_letter = ""
final_cipher = []
loop = 0
alphabet = string.ascii_lowercase + " " + string.ascii_lowercase + " "
while loop < len(final_positions_of_letters):
new_letter =alphabet[final_positions_of_letters[loop]]
final_cipher = str(final_cipher) + str(new_letter)
loop += 1
print final_cipher
This is a encryption/ decryption programme in python 2.7. However at the end of the programme when the final_cipher list is printed to the shell a pair of [] brackets are printed prior to the contents of the list

You have some options here:
• Loop through the array, and print each element on the same row without delimiter.
• Use 'join' to join all the parts of the array in a single string. You can find more information about the join statement here.
Personally I do think 'join' is the best option here.

I guess you are trying to output a string. And you are making a mistake by setting the initial declaration to an empty list.
For fixing this just use :
final_cipher = "" instead of final_cipher = []
This should get you the output in string format.

Seeing:
final_cipher = []
loop = 0
alphabet = string.ascii_lowercase + " " + string.ascii_lowercase + " "
while loop < len(final_positions_of_letters):
new_letter =alphabet[final_positions_of_letters[loop]]
final_cipher = str(final_cipher) + str(new_letter)
loop += 1
print final_cipher
I see that you are working with final_cipher like a string, then you should initialize like:
final_cipher = ""
And:
final_cipher = str(final_cipher) + str(new_letter)
Should be:
final_cipher = final_cipher + str(new_letter)
Or better:
final_cipher += str(new_letter)

final_cipher is a list, so yes, printing it will print it as a string, i.e. the result of calling str(final_cipher).
If you want to just print the elements seperated by a comma, you can use .join:
print ", ".join(final_cipher)

You create final_cipher as a list but then change your mind and do string concatenation instead. On the first iteration of the loop, str(final_cipher) creates the string representation of an empty list "[]". Look familiar? Keep a list and build the string at the end.
final_cipher = []
loop = 0
alphabet = string.ascii_lowercase + " " + string.ascii_lowercase + " "
while loop < len(final_positions_of_letters):
new_letter =alphabet[final_positions_of_letters[loop]]
final_cipher.append(str(new_letter))
loop += 1
final_cipher = ''.join(final_cipher)
print final_cipher

vigenere cipher - not adding correct values

I want to get specific values from a for loop to add to another string to create a vigenere cipher.
here's the code.
userinput = input('enter message')
keyword = input('enter keyword')
new = ''
for a in keyword:
pass
for i in (ord(x) for x in userinput):
if 96 < i < 123: #lowercase
new += chr(97 + (i+ord(a)-97)#keeps all values in alphabet
print(new)
so the answer i want if i do 'abcd' as my message and 'ab' as my keyword the desired outcome is 'bddf' as 'a' + 'a' is 'b' and 'b' + 'b' = 'd' and etc. how would i change the code to match my desired outcome or will i have to change it completely and how would i go about doing so.

try this (you are missing the mod 26-part):
from itertools import cycle
plaintext = input('enter message: ')
keyword = input('enter keyword: ')
def chr_to_int(char):
return 0 if char == 'z' else ord(char)-96
def int_to_chr(integer):
return 'z' if integer == 0 else chr(integer+96)
def add_chars(a, b):
return int_to_chr(( chr_to_int(a) + chr_to_int(b) ) % 26 )
def vigenere(plaintext, keyword):
keystream = cycle(keyword)
ciphertext = ''
for pln, key in zip(plaintext, keystream):
ciphertext += add_chars(pln, key)
return ciphertext
ciphertext = vigenere(plaintext, keyword)
print(ciphertext)
if you like list comprehensions, you can also write
def vigenere(plaintext, keyword):
keystream = cycle(keyword)
return ''.join(add_chars(pln, key)
for pln, key in zip(plaintext, keystream))
UPDATE
updated according to the wish that a+a=b. note that z is in that case the neutral element for the addition (z+char=z).