So I am learning python and am trying to count the number of vowels in a sentence. I figured out how to do it both using the count() function and an iteration but now I am trying to do it using recursion. When I try the following method I get an error "IndexError: string index out of range". Here is my code.
sentence = input(": ")
def count_vowels_recursive(sentence):
total = 0
if sentence[0] == "a" or sentence[0] == "e" or sentence[0] == "i" or sentence[0] == "o" or sentence[0] == "u":
total = total + 1 + count_vowels_recursive(sentence[1:])
else:
total = total + count_vowels_recursive(sentence[1:])
return the_sum
print(count_vowels_recursive(sentence))
Here are my previous two solutions.
def count_vowels(sentence):
a = sentence.count("a")
b = sentence.count("e")
c = sentence.count("i")
d = sentence.count("o")
e = sentence.count("i")
return (a+b+c+d+e)
def count_vowels_iterative(sentence):
a_ = 0
e_ = 0
i_ = 0
o_ = 0
u_ = 0
for i in range(len(sentence)):
if "a" == sentence[i]:
a_ = a_ + 1
elif "e" == sentence[i]:
e_ = e_ + 1
elif "i" == sentence[i]:
i_ = i_ + 1
elif "o" == sentence[i]:
o_ = o_ + 1
elif "u" == sentence[i]:
u_ = u_ + 1
else:
continue
return (a_ + e_ + i_ + o_ + u_)
You have no base case. The function will keep recursing until sentence is empty, in which case your first if statement will cause that index error.
You should first of all check if sentence is empty, and if so return 0
You can shorten things up quite a bit:
def count_vowels_recursive(sentence):
# this base case is needed to stop the recursion
if not sentence:
return 0
# otherwise, sentence[0] will raise an exception for the empty string
return (sentence[0] in "aeiou") + count_vowels_recursive(sentence[1:])
# the boolean expression `sentence[0] in "aeiou"` is cast to an int for the addition
You can try this:
def count_vowels_recursive(s, count):
if not s:
return count
else:
new_count = count
if s[0] in ["a", "e", "i", "o", "u"]:
new_count += 1
return count_vowels_recursive(s[1:], new_count)
Related
My Problem is on line 25 when it says
if conformation == 1:
for i in range(l, len(lines[k]), 1):
if lines[k][i].isdigit() or lines[k][i].istitle():
f += lines[k][i]
if f in var:
print(var[f])
What my issue is is that the "f" string isn't being added to and its value stays as "". For context, I'm trying to make my own sort of mini programming language, and I'm trying to make prints read for variables. Every time it loops to set f to the variable name, nothing happens. The only way I get remotely close to finding the variable name is by doing "print(lines[k][i])" before the "if lines[k][i]" condition.
Note: I was using a debugger, and I'm not sure if the "if f in var" condition is even being checked.
Python code that reads my custom programming language:
⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄
code = open("HelloWorld.sabo", 'r')
lines = code.readlines()
var = {}
for k in range(0, len(lines), 1):
conformation = 0
temp = ""
temp2 = ""
if lines[k][0:5] == "print":
r = 0
l = 0
p = False
f = ""
for i in lines[k]:
r += 1
if not p:
l += 1
if i == "(":
p = True
conformation += 1
if i == "\"" and conformation == 1:
conformation += 1
if conformation == 2:
break
if conformation == 1:
for i in range(l, len(lines[k]), 1):
if lines[k][i].isdigit() or lines[k][i].istitle():
f += lines[k][i]
if f in var:
print(var[f])
if conformation == 2:
for i in range(r, len(lines[k]), 1):
if not lines[k][i] == "\"":
f += lines[k][i]
else:
break
print(f)
elif lines[k][0:4] == "var ":
for i in range(4, len(lines[k]), 1):
if not lines[k][i] == " ":
temp += lines[k][i]
else: break
for i in range(4, len(lines[k])):
if lines[k][i] == "=":
conformation = 1
elif conformation == 1:
if not lines[k][i] == " ":
temp2 += lines[k][i]
elif not temp2 == "":
break
var[temp] = temp2.strip()
Code that is being read by the above script:
⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄
var val = hello
print(val)
So, I was being a bit dumb with this, but I found out that if I just account for Uppercase and Lowercase characters, then it will work.
if lines[k][i].islower() or lines[k][i].isdigit() or lines[k][i].isnumeric() or lines[k][i].istitle():
f += lines[k][i]
I might have gone overboard with the security though I'm just not sure about the difference isdigit and isnumeric.
I'm currently learning Python and I'm stuck on this specific question.
Image
Here is my current code:
word = input()
text = 0
wordch = 0
positions = 0
repeated = 0
while repeated != 2:
for i in range(0, len(tablet)):
if tablet[i] == word[wordch]:
text += 1
wordch += 1
if text == len(word):
positions += 1
text = 0
wordch = 0
elif repeated == 1 and text == len(word):
positions += 1
text = 0
wordch = 0
break
elif i == len(tablet)-1:
repeated += 1
break
elif tablet[i] != word[wordch]:
text == 0
wordch == 0
print(positions)
I would hope for a code that is really basic using the same concepts but please do answer.
Thank you!
I have tried to solve the problem by using a different approach. As we know that we can only use (len(fav_word)) - 1 letters if we tried to create the substring in a cyclic manner from the end since if we took any more characters, we would have created them from the start itself without the cycle.
So, I just created a new string from the original string by appending the starting (len(fav_word)) - 1 to the original string and then find all occurrences of the fav_string in the new string.
def find_all(a_str, sub):
start = 0
while True:
start = a_str.find(sub, start)
if start == -1: return
yield start
start += 1
x = "cabccabcab"
fav = "abc"
y = x + x[0:len(fav)-1]
print(len(list(find_all(y, fav)))) # Output: 3
x = "ababa"
fav = "aba"
y = x + x[0:len(fav)-1]
print(len(list(find_all(y, fav)))) # Output: 2
x = "aaaaaa"
fav = "aa"
y = x + x[0:len(fav)-1]
print(len(list(find_all(y, fav)))) # Output: 6
x = "abaaba"
fav = "aaba"
y = x + x[0:len(fav)-1]
print(len(list(find_all(y, fav)))) # Output: 2
def find_str(g,find):
lg = len(g)
lf = len(find)
x=0
s=""
for index, i in enumerate(g):
if i == find[0]:
if index+lf <= lg:
s = "".join(g[index:index+lf])
if s == find:
x+=1
else:
rem = "".join(g[index:])
lr = len(rem)
for index,i in enumerate(g):
rem+=i
lr+=1
if lr == lf:
if rem == find:
x+=1
break
return x
print(find_str("abaaba","aaba"))
def split(word):
return [char for char in word]
x = "aaaaaa"
pattern = "aa"
mylist=split(x)
ok=True
occurrences=0
buffer=""
while ok:
char=mylist.pop(0)
buffer+=char
if buffer==pattern:
occurrences+=1
buffer=""
if len(mylist)==0:
ok=False
print(occurrences)
output:3
I am writing a code and want to make it as short as possible, is there any way i can?
text = raw_input("Give me some text > ")
list1 = []
for char in text:
num = ord(char)
if num in range(48,57):
print "ERROR 319: Number entered"
quit()
elif num in range(65,90) or num in range (97,122):
upper = char.upper()
list1.append(upper)
num1 = 0
vowelCount = 0
conCount = 0
for x in range(len(list1)):
if list1[num1] == "A" or list1[num1] == "E" or list1[num1] == "I" or list1[num1] == "O" or list1[num1] == "U":
vowelCount = vowelCount + 1
else:
conCount = conCount + 1
num1 = num1 + 1
print "Vowels: " +str(vowelCount) + " Consonants: " + str(conCount)
Instead of taking ord() of the character, you can use the string methods:
char.isdigit() # check if a char is a digit
char.isalpha() # check if char is letter
For checking the vowel counts, try:
vowel_count = len(filter(lambda c: c in "aeiou", list1))
cons_count = len(list1) - vowel_count
Building off of AmourK's answer, you could do something like this:
text = raw_input("Give me some text > ")
vowel_count = len(filter(lambda c: c in "aeiou", text))
cons_count = len(filter(lambda c: c not in "aeiou" and c.isalpha(), text))
print "Vowels: %d Consonants: %d" % (vowel_count, cons_count)
I'm having a lot of trouble converting infix notation to postfix.
For instance, I want to convert this
test(a(b+c), d()) - 3
into this
b c + a , d test 3 -
I tried this solution,
def composition(s):
i = 0
rpnstack = []
stack = []
ret = []
count = 0
while i < len(s) :
if i + 1 < len(s) and s[i + 1] == "(":
stack.append([count, rpnstack, s[i]])
i += 2
count = 1
rpnstack = []
elif s[i] == "(":
count += 1
rpnstack.append(s[i])
i += 1
elif s[i] == ")":
count -= 1
if count == 0:
for a in rpn(rpnstack):
ret.append(a)
a = stack.pop()
count = a[0]
rpnstack = a[1]
ret.append(a[2])
else:
rpnstack.append(s[i])
i += 1
else:
rpnstack.append(s[i])
i += 1
for a in rpn(rpnstack):
ret.append(a)
return ret
where RPN is the standard algorithm for the reverse polish notation and is is the infix string splitted with this regex
(\+|\-|\*|\/|\>|\<|\(|\)|\,)
But it only works sometimes.
This is the full implementation of the rpn function
operator = -10
operand = -20
leftparentheses = -30
rightparentheses = -40
empty = -50
operands = ["+", "-", "*", "/", ">", "<", "=", ","]
def precedence(s):
if s is '(':
return 0
elif s is '+' or '-':
return 1
elif s is '*' or '/' or '%':
return 2
else:
return 99
def typeof(s):
if s is '(':
return leftparentheses
elif s is ')':
return rightparentheses
elif s in operands:
return operator
elif s is ' ':
return empty
else :
return operand
def rpn(infix):
postfix = []
temp = []
for i in infix :
type = typeof(i)
if type is leftparentheses :
temp.append(i)
elif type is rightparentheses :
next = temp.pop()
while next is not '(' or skip > 0:
postfix.append(next)
next = temp.pop()
elif type is operand:
postfix.append(i)
elif type is operator:
p = precedence(i)
while len(temp) is not 0 and p <= precedence(temp[-1]) :
postfix.append(temp.pop())
temp.append(i)
elif type is empty:
continue
while len(temp) > 0 :
postfix.append(temp.pop())
return postfix
if i try to use the code against this infix expression:
i < test.func()
i get:
[' test.func', 'i ', '<']
and against this
i < 10
i get:
['i ', ' 10', '<']
How can I fix this?
SO i have this assignment to translate multiple words into pig latin. assume that the user will always input lowercase and only letters and spaces.
#----------------global variables
sentence = input("What do you want to translate into piglattin? ")
sentence = list(sentence)
sentence.insert(0, ' ')
length = len(sentence)
sentence.append(' ')
pigLattin = sentence
false = 0
true = 1
consonant = []
a = 0
b = 0
c = 0
d = 0
e = 0
f = 0
j = 0
x = 0
y = 0
#----------------main functions
def testSpace(sentence, i):
if sentence[i] == ' ':
a = true
else:
a = false
return a
def testVowel(sentence, i):
if sentence[i] == 'a' or sentence[i] == 'e' or sentence[i] == 'i' or sentence[i] == 'o' or sentence[i] == 'u' or sentence[i] == 'y':
b = true
else:
b = false
return b
def testStartWord(sentence, i):
x = 0
if sentence[i].isalpha() and sentence[i-1] == ' ':
c = true
x = 1
if x == 1 and sentence[i] != 'a' and sentence[i] != 'e' and sentence[i] != 'i' and sentence[i] != 'o' and sentence[i] != 'u' and sentence[i] != 'y':
c = true
else:
c = false
return c
def testWordEnd(sentence, i):
if sentence[i].isalpha() and sentence[i+1] == ' ':
d = true
else:
d = false
return d
#----------------main loop
for i in range(1,length):
x = 0
space = testSpace(sentence, i)
vowel = testVowel(sentence, i)
word = testStartWord(sentence, i)
end = testWordEnd(sentence, i)
if vowel == false and space == false and word == true:
e = i
consonant.append(sentence[i])
pigLattin.pop(e)
f = f + 1
if end == true:
consonant.append('a')
consonant.append('y')
consLength = len(consonant)
for x in range(consLength):
y = i + j - f
pigLattin.insert(y,consonant[x])
j = j + 1
del consonant[:]
pigLength = len(pigLattin)
for b in range (pigLength):
print(pigLattin[b], end='')
this is what i have so far. it gets kinda messy when trying to remove items. im sort of stuck here and its not working.
OK i got it working now this is an updated version
sentence = input("Please enter a sentence: ")
vowels = ("a", "e", "i", "o", "u", "A", "E", "I", "O", "U")
words = sentence.split()
count = 0
def find_vowel(word):
for i in range(len(word)):
if word[i] in vowels:
return i
return -1
for word in words:
vowel = find_vowel(word)
if(vowel == -1):
print(word, ' ', end='')
elif(vowel == 0):
print(word + "ay", ' ', end='')
else:
print(word[vowel:] + word[:vowel] + "ay", ' ', end='')
Instead of using testSpace eliminate the spaces by using sentence = sentence.split(). This will split all your words into strings in a list. Then iterate through the words in your list.
Instead of using testStartWord, use an if statement:
for word in sentence:
if word[0] in ["a","e","i","o","u"]:
word[:(len(word)-1)] = word[0]
#More Code...
At the end, where you print the output, use print sentence.join()
Here's an alternate version. I use a regular expression to find words in the input string, pass them to a callback function, and substitute them back into the original string. This allows me to preserve numbers, spacing and punctuation:
import re
import sys
# Python 2/3 compatibility shim
inp = input if sys.hexversion >= 0x3000000 else raw_input
VOWELS = set('aeiouyAEIOUY')
YS = set('yY')
def pig_word(word):
"""
Given a word, convert it to Pig Latin
"""
if hasattr(word, 'group'):
# pull the text out of a regex match object
word = word.group()
# find the first vowel and what it is
vowel, where = None, None
for i,ch in enumerate(word):
if ch in VOWELS:
vowel, where = ch, i
break
if vowel is None:
# No vowels found
return word
elif where == 0 and vowel not in YS:
# Starts with a vowel - end in 'way'
# (leading y is treated as a consonant)
return word + 'way'
else:
# Starts with consonants - move to end and follow with 'ay'
# check capitalization
uppercase = word.isupper() and len(word) > 1
titlecase = word[:1].isupper() and not uppercase
# rearrange word
word = word[where:] + word[:where] + 'ay'
# repair capitalization
if uppercase:
word = word.upper()
elif titlecase:
# don't use str.title() because it screws up words with apostrophes
word = word[:1].upper() + word[1:].lower()
return word
def pig_latin(s, reg=re.compile('[a-z\']+', re.IGNORECASE)):
"""
Translate a sentence into Pig Latin
"""
# find each word in the sentence, pass it to pig_word, and insert the result back into the string
return reg.sub(pig_word, s)
def main():
while True:
s = inp('Enter a sentence to translate (or Enter to quit): ')
if s.strip():
print(pig_latin(s))
print('')
else:
break
if __name__=="__main__":
main()
then
Enter a sentence to translate (or Enter to quit):
>>> Hey, this is really COOL! Let's try it 3 or 4 times...
Eyhay, isthay isway eallyray OOLCAY! Et'slay ytray itway 3 orway 4 imestay...