Day 22- String Functions and Recursion

1.Write a program to add space between the strings.

txt = "TodayIsFriday"
first = True
for letter in txt:
    if letter>='A' and letter<='Z':
        if first==True:
            first = False
        else:
            print(' ',end='')
    print(letter,end='')

Today Is Friday

2.Write a program to remove space between the strings.

txt = "    Today Is Friday"
for letter in txt:
    if letter==' ':
        pass
    else:
        print(letter,end='')

TodayIsFriday

3.Write a program to remove space in the left side of the string:

ltrim()-to remove any leading whitespace or specified characters from the left side of a string.

txt = "    Today Is Friday"
alphabet = False
for letter in txt:
    if letter==' ' and alphabet==False:
        pass
    else:
        alphabet = True
        print(letter,end='')

Today Is Friday

4.Write a program to remove space in the right side of the string:

rtrim()-to remove any leading whitespace or specified characters from the right side of a string.

txt = "Today Is Friday   "
alphabet = False
i = len(txt)-1
while i>=0:
    letter = txt[i]
    if letter==' ' and alphabet == False:
        pass
    else:
        alphabet = True
        end = i
        j = 0
        while j<=end:
            print(txt[j],end='')
            j+=1
        break
    i-=1     

Today Is Friday

5.Write a program to remove unwanted space from the given string:

txt = "Today              Is                       Friday"
i = 0 
while i<len(txt):
    if txt[i] != ' ':
        print(txt[i],end='')
    else:
        if txt[i-1]!=' ':
            print(txt[i],end='')
    i+=1  

Today Is Friday

Recursion:
Function calling itself.

what is function?
Set if instructions with a name for achieving a specific task.

Looping-Iterative approach.
Recursion-Recursive approach.

Example:

def display(no):
    print(no, end=' ')
    no+=1
    if no<=5:
        display(no)
display(1)

1 2 3 4 5

Write a factorial program using recursion:

def find_fact(no):
    if no==1:
        return 1
    return no * find_fact(no-1)

result = find_fact(4)
print(result)

24

Task:
Write a program to remove unwanted space from the given string:

strip()-Removes all white space characters from the start and end of the string.

txt = "    Today Is Friday    "
first=True
for letter in txt:
    if letter==" ":
        pass
    else:
        if letter>='A' and letter<='Z':
            if first==True:
                first = False
            else:
                print(' ',end='')
        print(letter,end='')

Today Is Friday

Write a program to given number in reverse order using recursion:

def reverse_number(num,reverse=0):
    if num==0:
        return reverse
    return reverse_number(num//10,reverse*10+num%10)
num=int(input("Enter the number:"))
print(reverse_number(num))

Enter the number:123
321

Write a program to find the given number is palindrome or not using recursion:

def palindrome(num,count=0):
    if num==0:
        return count
    return palindrome(num//10,count*10+num%10)

num=int(input("Enter the number:"))
result=palindrome(num)
if result==num:
    print("Palindrome")
else:
    print("Not palindrome")

Enter the number:1221
Palindrome
Enter the number:56878
Not palindrome

Write a program to find fibonacci number using recursion:

def find_fibonacci(first_num,sec_num,no):
    if first_num > no:
        return
    print(first_num, end=" ")

    find_fibonacci(sec_num,first_num+sec_num,no)      

no = int(input("Enter the number: ")) 
find_fibonacci(0,1,no)

0 1 1 2 3 5 8

write a program to find prime number using recursion:

def find_prime(no,div=2):
    if div<no:
        if no%div == 0:
            return False
        div+=1
        return find_prime(no,div)
    else:
        return True

no = int(input("Enter no. "))
print(find_prime(no))

Enter no. 12
False