i have written this code which checks whether a number is correctly represented in a given base. for all the invalid cases it gives false but for true ones it says string index out of range.
def check(n,a,i=0):
if int(n[i])>=a :
return False
else:
return check(n,a,i+1)
n = str(input('enter no:'))
a =int(input('enter base:'))
print(check(n,a,i=0))
The pythonic way:
def is_base_x(num_string, base):
for single_char in num_string:
if int(single_char) >= int(base):
return False
return True
As #ooga pointed out, you need to check when i is larger than the length of your number, you can make it like:
def check(n,a,i=0):
if len(n) <= i:
return True
if int(n[i])>=a :
return False
else:
return check(n,a,i+1)
n = str(input('enter no:'))
a = int(input('enter base:'))
print(check(n,a,i=0))
It would be better if it could check bases above 10. Something like this:
import string
def check(num, base, i = 0):
if i >= len(num):
return True
if not num[i].isdigit():
val = string.ascii_lowercase.find(num[i].lower())
if val == -1 or val + 10 >= base:
return False
elif int(num[i]) >= base:
return False
return check(num, base, i + 1)
while True:
num = raw_input('Enter number: ')
if len(num) == 0: break # null string breaks
base = int(raw_input('Enter base: '))
print(check(num, base))
Related
I need to write a code that prints out valid or invalid for an input of letters and numbers for a license plate. The conditions are: first two characters must be letters, characters have to be between 2 and 6, and if numbers are used, 0 should not be the first, nor should a number appear before a letter.
I put the code below on Thonny and cannot understand why len(l) == 4 part of the conditional statement for def valid_order() returns None and does not execute the next line of the code whereas others work fine. My code should return "Valid" for CSAA50, but it returns invalid. Why?
Also, is there an elegant way to write def valid_order()?
def main():
plate = input("Plate: ")
if is_valid(plate):
print("Valid")
else:
print("Invalid")
def is_valid(s):
if s[0:2].isalpha() and 6 >= len(s) >= 2 and s.isalnum() and valid_order(s):
return True
else:
return False
def valid_order(c):
n = []
l = list(c[2:len(c)])
for i in c:
if i.isdigit():
n += i
if n and n[0] == "0":
return False
if len(l) == 2:
if l[0].isdigit() and l[1].isalpha():
return False
if len(l) == 3:
if l[0].isdigit():
if l[1].isalpha() or l[2].isalpha():
return False
else:
if l[1].isdigit() and l[2].isalpha():
return False
if len(l) == 4:
if l[0].isdigit():
if l[1].isalpha() or l[2].isalpha() or l[3].isalpha():
return False
else:
if l[1].isdigit():
if l[2].isalpha() or l[3].isalpha():
return False
else:
if l[2].isdigit() and l[3].isalpha():
return False
else:
return True
main()
There was a question which asked to write a code, to get continuous integer input from user until a negative integer is input and for each input I should evaluate if it is a palindrome in both base 10 and 2. If yes then print 'Yes' else print 'No'.
For example: 99 = (1100011)base2, both versions are palindrome so it prints 'Yes'
This is a usual elementary method.
while 1:
num = int(input('Input: '))
if num > 0:
num1 = str(num)
if num1 == num1[::-1]:
list1 = list(bin(num))
list1.pop(0)
list1.pop(0)
n = ''.join(list1)
if n == n[::-1]:
print('Yes')
else:
print('No')
else:
print('No')
else:
break
But when I tried to type a code using defining a new function it didn't work well. Here following is the code. Can you note what is wrong with this.
def palindrome(n):
n = str(n)
if n == n[::-1]:
return True
else:
return False
def b2_palindrome(n):
list1 = list(bin(n))
list1.pop(0)
list1.pop(0)
n = ''.join(list1)
palindrome(n)
while 1:
num = int(input('Input: '))
if num > 0:
if b2_palindrome(num) and palindrome(num):
print('Yes')
else:
print('No')
else:
break
#dspencer: edited the indentations
you're not returning the value of the palindrome call in b2_palindrome
see below:
def b2_palindrome(n):
list1 = list(bin(n))
list1.pop(0)
list1.pop(0)
n = ''.join(list1)
return palindrome(n) # <-- added return here
I'm looking to write a function definition named has_evens that takes in sequence of numbers and returns True if there are any even numbers in the sequence and returns False otherwise.
My code is correct, except when it receives something empty, like "([])". I need to account for that. Here's my code:
def has_evens(s):
for num in s:
if num % 2 == 0:
return True
elif num % 2 != 0:
return False
if ([]):
return False
The final part is a desperate attempt to account for blank lists. More formally, it needs to pass this assertion:
assert has_evens([]) == False
You should only return True when an even is found:
def has_evens(s):
for num in s:
if num % 2 == 0:
return True
return False
Python has an any function to make this simpler:
def has_evens(s):
return any(num % 2 == 0 for num in s)
I answered my own question. I just needed to un-indent my lines
def has_evens(s):
for num in s:
if num % 2 == 0:
return True
else:
return False
So my task is to see and check a positive integer if its a palindrome. I've done everything correctly but need help on the final piece. And that the task of generating a new a palindrome from the one given given by the user. Am i on the right track with the while loop or should i use something else? So the result is if you put 192 it would give back Generating a palindrome....
483
867
1635
6996
"""Checks if the given, positive number, is in fact a palindrome"""
def palindrome(N):
x = list(str(N))
if (x[:] == x[::-1]):
return True
else: return False
"""Reverses the given positive integer"""
def reverse_int(N):
r = str(N)
x = r[::-1]
return int(x)
def palindrome_generator():
recieve = int(input("Enter a positive integer. "))
if (palindrome(recieve) == True):
print(recieve, " is a palindrome!")
else:
print("Generating a palindrome...")
while palindrome(recieve) == False:
reverse_int(recieve) + recieve
If I understand your task correctly, the following should do the trick:
def reverse(num):
return num[::-1]
def is_pal(num):
return num == reverse(num)
inp = input("Enter a positive number:")
if is_pal(inp):
print("{} is a palindrome".format(inp))
else:
print("Generating...")
while not is_pal(inp):
inp = str(int(inp) + int(reverse(inp)))
print(inp)
The variable inp is always a string and only converted to int for the arithmetic.
I've been using this solution for many years now to check for palindromes of numbers and text strings.
def is_palindrome(s):
s = ''.join(e for e in str(s).replace(' ','').lower() if e.isalnum())
_len = len(s)
if _len % 2 == 0:
if s[:int(_len/2)] == s[int(_len/2):][::-1]:
return True
else:
if s[int(_len/2+1):][::-1] == s[:int(_len/2)]:
return True
return False
This one is using Complement bitwise and Logical AND and OR operators
_input = 'Abba' # _input = 1221
def isPalindrome(_):
in_str = str(_).casefold() # Convert number to string + case insensitive
for _ in range(int(len(in_str) / 2)): # Loop from 0 till halfway
if in_str[_] != in_str[~_]:
return False
return True
print(_input, isPalindrome(_input) and ' is palindrome' or ' is not palindrome')
Abba is palindrome
MyFunctions file file -
def factList(p,n1):
counter = 1
while counter <= n1:
if n1 % counter == 0:
p.append(counter)
counter = counter + 1
def isPrime(lst1,nbr):
factList(lst1, nbr)
if len(lst1) == 2:
return True
else:
return False
def nextPrime(nbr1):
cnt1 = 1
while cnt1 == 1:
nbr1 == nbr1 + 1
if isPrime(lst2,nbr1):
cnt1 = 0
Filetester file -
nbr1 = 13
nextPrime(nbr1)
print nbr1
My isPrime function already works I'm tring to use my isPrime function for my nextPrime function, when I run this I get
">>>
13
" (when using 13)
">>> " (When using 14)
I am supposed to get 17 not 13. And if I change it to a composite number in function tester it gets back in a infinite loop. Please only use simple functions (the ones I have used in my code).
This is NOT the right way to do this, but this is the closest adaptation of your code that I could do:
def list_factors_pythonic(number):
"""For a given number, return a list of factors."""
factors = []
for x in range(1, number + 1):
if number % x == 0:
factors.append(x)
return factors
def list_factors(number):
"""Alternate list_factors implementation."""
factors = []
counter = 1
while counter <= number:
if number % counter == 0:
factors.append(counter)
return factors
def is_prime(number):
"""Return true if the number is a prime, else false."""
return len(list_factors(number)) == 2
def next_prime(number):
"""Return the next prime."""
next_number = number + 1
while not is_prime(next_number):
next_number += 1
return next_number
This would be helpful:
def nextPrime(number):
for i in range(2,number):
if number%i == 0:
return False
sqr=i*i
if sqr>number:
break
return True
number = int(input("Enter the num: ")) + 1
while(True):
res=nextPrime(number)
if res:
print("The next number number is: ",number)
break
number += 1
I don't know python but if it's anything like C then you are not assigning anything to your variables, merely testing for equality.
while cnt1 == 1:
nbr1 == nbr1 + 1
if isPrime(lst2,nbr1):
cnt1 == cnt1 + 1
Should become
while cnt1 == 1:
nbr1 = nbr1 + 1 << changed here
if isPrime(lst2,nbr1):
cnt1 = cnt1 + 1 << and here
Well this code help you
n=int(input())
p=n+1
while(p>n):
c=0
for i in range(2,p):
if(p%i==0):
break
else:c+=1
if(c>=p-2):
print(p)
break
p+=1
this code optimized for finding sudden next prime number of a given number.it takes about 6.750761032104492 seconds
def k(x):
return pow(2,x-1,x)==1
n=int(input())+1
while(1):
if k(n)==True:
print(n)
break
n=n+1