Both codes work(caesar cipher): but one code rearranges the output - python

Beginner python programmer here. Before I knew about using .index(), i used a work around. Whilst it did work something peculiar happened. The output string was re-arranged and i don't know why.
Here is my code:
alphabet = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
text = input("Type your message:\n").lower()
shift = int(input("Type the shift number:\n"))
#input for text = "code" integer for shift = 5
#First attempt
for index, price in enumerate(alphabet):
new_index = shift + index
for loop in text:
if loop == price:
print(alphabet[new_index])
#Second attempt using .index
for letter in text:
position = alphabet.index(letter)
new_index = position + shift
print(alphabet[new_index])
Here are the outputs
output for first code = hijt
output for second code = htij

Your first code prints the word with the letters rearranged in alphabetical order (before using the cipher). You go through the alphabet in your enumerate, a-z, and you look for each letter in your word. For example, if your word was 'ba', with a shift of one, it should output 'cb' - but it outputs 'bc'. It is because your loop looks for 'a's and prints the converted values out before doing so for 'b's.
Your second is correct.
Note: I have no idea why your sample output is on a single line - print generally adds a newline, so each letter would have been on a separate line. Also, you should realize that your code doesn't work when the new letter goes past 'z' - it has an index out of range error.

Related

Python ignore punctuation and white space

string = "Python, program!"
result = []
for x in string:
if x not in result:
result.append(x)
print(result)
This program makes it so if a repeat letter is used twice in a string, it'll appear only once in the list. In this case, the string "Python, program!" will appear as
['P', 'y', 't', 'h', 'o', 'n', ',', ' ', 'p', 'r', 'g', 'a', 'm', '!']
My question is, how do I make it so the program ignores punctuation such as ". , ; ? ! -", and also white spaces? So the final output would look like this instead:
['P', 'y', 't', 'h', 'o', 'n', 'p', 'r', 'g', 'a', 'm']
Just check if the string (letter) is alphanumeric using str.isalnum as an additional condition before appending the character to the list:
string = "Python, program!"
result = []
for x in string:
if x.isalnum() and x not in result:
result.append(x)
print(result)
Output:
['P', 'y', 't', 'h', 'o', 'n', 'p', 'r', 'g', 'a', 'm']
If you don't want numbers in your output, try str.isalpha() instead (returns True if the character is alphabetic).
You can filler them out using the string module. This build in library contains several constants that refer to collections of characters in order, like letters and whitespace.
import string
start = "Python, program!" #Can't name it string since that's the module's name
result = []
for x in start:
if x not in result and (x in string.ascii_letters):
result.append(x)
print(result)

Python: TypeError: unsupported operand type(s) for +: 'Random' and 'str'

I'm entering a code where a word is randomly generated. But it says TypeError and that random can't be matched with string
I've tried rewriting code multiple times but it didn't work.
Code:
import random
from random import *
Letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
LettersInWord = Random()
Points = 0
print(LettersInWord + " is number of letters in word")
for index in range(LettersInWord):
Word = Letters[Random.random(0, 25)]
Guess = input("Enter Word You Think It Is (You will get a point everytime
one or more of your letters match with the word. Your turn will end when
you enter a letter that is not in the word: ")
for letter in Guess:
if letter == letter in Word:
Points = Points + 1
if Guess == Word:
print("Congratulations, you won. End program and restart to
try again.")
Guess = input("Well done, try again")
Random() is a random-number generator, not a number itself.
letters_in_word = randint(1,25) # random number between 1 and 25, inclusive
(Capitalized names are conventionally reserved for class names. Use snake case identifiers for ordinary variables.)
Continuing from the comments:
from random import *
Letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
while True:
letters_in_word = randint(1,25)
Points = 0
Word = []
print("{} is number of letters in word".format(letters_in_word))
for index in range(0, letters_in_word):
Word.append(Letters[randint(0, 25)])
Guess = input("Press Q/q to exit or Enter Word You Think It Is (You will get a point everytime one or more of your letters match with the word. Your turn will end when you enter a letter that is not in the word: ")
if Guess.lower() == 'q':
break
print(Word)
if Guess in Word:
Points = 100 # assuming
print("Congratulations, you won. End program and restart to try again.\nTotal Points: {}".format(Points))
break
else:
for letter in Guess:
if letter in Word:
Points = Points + 1
print("Total Points: {}".format(Points))
OUTPUT:
10 is number of letters in word
Press Q/q to exit or Enter Word You Think It Is (You will get a point everytime one or more of your letters match with the word. Your turn will end when you enter a letter that is not in the word: pak
['f', 't', 'l', 'b', 'd', 'k', 'e', 'p', 'd', 'n']
Total Points: 2
9 is number of letters in word
Press Q/q to exit or Enter Word You Think It Is (You will get a point everytime one or more of your letters match with the word. Your turn will end when you enter a letter that is not in the word: dirt
['z', 'i', 'k', 'p', 'z', 'j', 'r', 't', 'd']
Congratulations, you won. End program and restart to try again.
Total Points: 100
Process finished with exit code 0

Confused on Python for loop behavior and if statement

I was hoping someone could explain this behaviour to me and what is going on.
If I run the following code:
phrase = "Don't Panic!"
phraseList = list(phrase)
print(phrase)
print(phraseList)
ontap = ['o', 'n', 't', 'a', 'p']
for letter in phraseList:
print("Letter ", letter)
#if letter not in ontap:
# phraseList.remove(letter)
print(phraseList)
I get the following expected output:
Don't Panic!
['D', 'o', 'n', "'", 't', ' ', 'P', 'a', 'n', 'i', 'c', '!']
Letter D
Letter o
Letter n
Letter '
Letter t
Letter
Letter P
Letter a
Letter n
Letter i
Letter c
Letter !
['D', 'o', 'n', "'", 't', ' ', 'P', 'a', 'n', 'i', 'c', '!']
However if I remove the comments I get this unexpected behaviour:
Don't Panic!
['D', 'o', 'n', "'", 't', ' ', 'P', 'a', 'n', 'i', 'c', '!']
Letter D
Letter n
Letter '
Letter
Letter a
Letter n
Letter i
Letter !
['o', 'n', 't', 'P', 'a', 'n', 'c']
So my question is, in the loop I would expect PRINT to be performed first before the list. remove function runs but it doesn't seem to work that way. Why? It seems to be skipping letters in the print like the letter C.
Also why does the compare seem to ignore the letter C when it clearly isn't in the ontap variable.
I am probably missing something extremely obvious. Does it have something to do with resizing the list and running a loop on it at the same time?
Thanks for any insight.
As the comments on the question confirm, the problem is indeed modifying phraseList while iterating over it. In a bit more detail, what's happening is this: when you go into the for loop, an iterator is created to iterate over phraseList. In the first iteration, the iterator supplies phraseList[0], which is D. This is not in the ontap list, so we do phraseList.remove('D'). On the next iteration, phraseList is now ['o', 'n', "'", 't', ...], but the iterator doesn't know it's changed - it just knows that now it needs to supply phraseList[1], which is now n. This is why the second iteration prints n, rather than o. c is never removed from phraseList because the only place it occurs is right after the first time i appears. When i is removed from phraseList, on the next loop, c is skipped. (Similarly, P is not removed because it's right after the first instance of <space>.)
The simplest way to fix your loop would be to iterate over a copy of phraseList:
for letter in list(phraseList):
print("Letter ", letter)
if letter not in ontap:
phraseList.remove(letter)
This way changing the original phraseList doesn't affect the iteration. You could also be more concise (and, in my opinion, more clear) with a list comprehension. The following accomplishes exactly what the for loop above does:
phraseList = [letter for letter in phraseList if letter in ontap]

Python Function That Receives Letter, Returns (0-Based) Numerical Position Within Alphabet

I'm trying to create a Python function that receives a letter (a string with only one alphabetic character) and returns the 0-based numerical position of that letter in the alphabet. It should not be case-sensitive, and I can't use import.
So entering "a" should return
0
Entering "A" should also return
0
Entering "O" should return
14
And so on.
I had noticed this question but the top answer uses import and the second answer doesn't make any sense to me / doesn't work. I tried to apply the second answer like this:
letter = input("enter a letter")
def alphabet_position(letter):
return ord(letter) - 97
print((alphabet_position)(letter))
but I got a TypeError:
TypeError: ord() expected a character, but string of length 2 found
Just like the asker in the question that I linked, I'm also trying to send the characters "x" amount of steps back in the alphabet, but in order to do that I need to create this helper function first.
I'm thinking there must be a way to store the letters in two separate lists, one lower-case and one upper-case, and then see if the string that the user entered matches one of the items in that list? Then once we find the match, we return it's (0-based) numerical position?
letter = input("enter a letter")
def alphabet_position(letter):
position = 0
#letter_position = index value that matches input
lower_case_list ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
'y', 'z']
upper_case_list ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y','Z']
#if letter is in lower_case_list, return it's 0-based numerical position.
#else, if letter is in upper_case_list, return it's 0-based numerical position.
#else, print("Enter a valid letter")
return letter_position
Please help if you have any suggestions. Thank you.
It's probably simpler to just convert from uppercase or lowercase to specifically lowercase with the .lower() method, and use the built in list of letters (string.ascii_lowercase). You can find the index of a list's element by using the .index() method.
import string
letter = input('enter a letter: ')
def alphabet_position(letter):
letter = letter.lower()
return list(string.ascii_lowercase).index(letter)
print(alphabet_position(letter))
When you called alphabet_position, it is expecting an argument so you need to do func_name(arg) format.
Another way you could do this is to use dictionary comprehension to create a dict of letter-position pairs, like so:
from string import lowercase as l
alphabet_lookup = {letter:pos for letter,pos in zip(l, range(len(l)))}
and then
f = lambda letter: alphabet_lookup[letter.lower()]
is the desired function.
I suggest using a dictionary. It might be a large amount of code to do something relatively simple, but I find it easier to make sense of it this way (and if you are new to python it will help you learn). If you google python dictionaries you can learn lots more about them, but here is the basic concept:
Code for python version 3.X:
def alphabet_position(letter):
alphabet_pos = {'A':0, 'a':0, 'B':1, 'b':1}
pos = alphabet_pos[letter]
return pos
letter = input('Enter a letter: ')
print(alphabet_position(letter))
Code for python version 2.7:
def alphabet_position(letter):
alphabet_pos = {'A':0, 'a':0, 'B':1, 'b':1}
pos = alphabet_pos[letter]
return pos
letter = raw_input('Enter a letter: ')
print alphabet_position(letter)
If you run that, it will print 1 because it searches through the alpahbet_pos dictionary and finds the value that corresponds to the entry entitled 'B'. Notice that you can have multiple entries with the same value, so you can do uppercase and lowercase in the same dictionary. I only did letters A and B for the sake of time, so you can fill out the rest yourself ;)
I once had to enter every element on the periodic table and their corresponding atomic mass, and that took forever (felt much longer than it actually was).

How to count the letters in a word? [duplicate]

This question already has answers here:
Letter Count on a string
(12 answers)
Closed 5 years ago.
I am trying to make a Python script which counts the amount of letters in a randomly chosen word for my Hangman game.
I already looked around on the web, but most thing I could find was count specific letters in a word. After more looking around I ended up with this, which does not work for some reason. If someone could point out the errors, that'd be greatly appreciated.
wordList = ["Tree", "Fish", "Monkey"]
wordChosen = random.choice(wordList)
wordCounter = wordChosen.lower().count['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
print(wordCounter)
Are you looking for collections.Counter?
>>> import collections
>>> print(collections.Counter("Monkey"))
Counter({'M': 1, 'y': 1, 'k': 1, 'o': 1, 'n': 1, 'e': 1})
>>> print(collections.Counter("Tree"))
Counter({'e': 2, 'T': 1, 'r': 1})
>>> c = collections.Counter("Tree")
>>> print("The word 'Tree' has {} distinct letters".format(len(c)))
The word 'Tree' has 3 distinct letters
>>> print("The word 'Tree' has {} instances of the letter 'e'".format(c['e']))
The word 'Tree' has 2 instances of the letter 'e'
First off, your code contains an error that is rather important to understand:
wordChosen.lower().count['a', 'b'] #...
count is a function and so it requires you to surround its parameters with parentheses and not square brackets!
Next you should try to refer to Python Documentation when using a function for the first time. That should help you understand why your approach will not work.
Now to address your problem. If you want to count the number of letters in your string use len(wordChosen) which counts the total number of characters in the string.
If you want to count the frequencies of each letter a few methods have already been suggested. Here is one more using a dictionary:
import string
LetterFreq={}
for letter in string.ascii_lowercase:
LetterFreq[letter] = 0
for letter in wordChosen.lower():
LetterFreq[letter] += 1
This has the nice perk of defaulting all letters not present in the word to a frequency of 0 :)
Hope this helps!
Problem:The count method only takes in one argument and you are trying to pass a whole list.
Solution:Simply iterate over all the letters, then test if they are in the string before you print them and their amount.
import random
wordList = ["Tree", "Fish", "Monkey"]
wordChosen = random.choice(wordList)
letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
for letter in letters:
if letter in wordChosen.lower():
amount = str(wordChosen.lower().count(letter))
print(letter + " : " + amount)
Result:If the random word chosen is "Tree":
e : 2
r : 1
t : 1
Conclusion:Using collections is definitely a more effective method, but I believe the way I have shown above creates more of the output you were looking for.

Categories

Resources