Counting vowels in a string

 Using count() method:

string_data=input("Enter a string:")
vowels={'a','e','i','o','u'}
# Using Count() Method
list1=[]
for ch in string_data:
	if ch in vowels:
		if ch not in list1:
			list1.append(ch)
			print("{} occurred {} times".format(ch,string_data.count(ch)))

Without using count() method:

string_data=input("Enter a string:")
vowels={'a','e','i','o','u'}
d={}
for ch in string_data:
	if ch in vowels:
		d[ch]=d.get(ch,0)+1

print(d)
for key,value in sorted(d.items()):
	print(key,"occurred",value,"times")

Counting number of occurrences of each character in a string

Using count() method:

string_data=input("Enter string: ")
l=[]
for x in string_data:
	if x not in l:
		l.append(x)
		print(x,"occurred",string_data.count(x),"times")

Without using count() method:

string_data=input("Enter string: ")
d={}
for x in string_data:
	d[x]=d.get(x,0) + 1
print(d)
print(d.items())
# for meaningful output
for key,value in sorted(d.items()):
	print(key,"occurred",value,"times")  

 

Question by Subscriber: 

 How to ignore special characters like ? , . etc

If you want to ignore special characters and focus on the alphabets and digits only, then you can do that by some extra work

You  can either import string class to get a set of all characters that you need to focus on, or you can manually add the set of characters you particularly want to focus on.

we will name them as valid_characters
Here goes the code:

import string
string_data=input("Enter string: ")
l=[]
valid_characters=set(string.ascii_letters+string.digits)
for x in string_data:
	if x in valid_characters:
		if x not in l:
			l.append(x)
			print(x,"occurred",string_data.count(x),"times")

Output: 

or

string_data=input("Enter string: ")
l=[]
valid_characters=set("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"+'0123456789')
for x in string_data:
	if x in valid_characters:
		if x not in l:
			l.append(x)
			print(x,"occurred",string_data.count(x),"times")

Hope you like it ..!

Removing duplicate characters from the string

 

 Sample Input: sssssssssssssssddddeeeeggggggghhhhh

Output: sdegh

1st way:

string_data=input("Enter string: ")
result=''
for character in string_data:
	if character not in result:
		result=result+character
print("You entered: ",string_data)
print("Final result after removing duplicate characters: \n", result )

  

2nd way:

string_data=input("Enter string: ")
list_data=[]

for character in string_data:
	if character not in list_data:
		list_data.append(character)
result="".join(list_data)		
print("You entered: ",string_data)
print("Final result after removing duplicate characters: \n", result )

Python Program for specific requirement-2

Sample Input: d8s2b5r6

Output:            dlsubgrx

string_data=input("Enter string: ")
result=''
for character in string_data:
	if character.isalpha():
		result=result+character
		previous=character
	else:
		digit=int(character)
		new_character=chr(ord(previous)+digit)
		result=result+new_character

print("You entered: ",string_data)
print("Final result : \n", result )

Python Program for specific requirements

Requirement:
Sample Input: s4b6c5a2d9

Output: ssssbbbbbbcccccaaddddddddd

string_data=input("Enter string: ")
result=''
for character in string_data:
	if character.isalpha():
		alphabet=character
	else:
		digit=int(character)
		result=result+alphabet*digit
print("You entered: ",string_data)
print("Final result: \n", result )

Requirement:
Sample Input:ssssbbbbbbcccccaaddddddddd

Output: 4s6b5c2a9d    

string_data=input("Enter string: ")
result=''
previous=string_data[0]
character_count=1
i=1
while i<len(string_data):
	if string_data[i]==previous:
		character_count=character_count+1
	else:
		result=result+str(character_count)+previous
		previous=string_data[i]
		character_count=1
	if i==len(string_data)-1:
		result=result+str(character_count)+previous
	i=i+1
print("You entered: ",string_data)
print("Final result: \n", result )

Sort characters in a string

 Assume input string contains only alphabet symbols and digits.

We need to write a program to sort characters of the string were we will sort alphabets first and then digits will follow

Sample Input: C8N9A2U6R5B7

Output: ABCNRU256789

string_data=input("Enter some alphanumeric string to sort: ")
alphabets=[]
digits=[]
for ch in string_data:
	if ch.isalpha():
		alphabets.append(ch)
	else:
		digits.append(ch)
result=''.join(sorted(alphabets)+sorted(digits))
print("You entered: ",string_data)

print("Final result after Sorting: \n", result )

Merge two strings

 Merge two strings by taking characters alternatively from each string

Sample string 1 :  PYTHON
Sample string 2 :  python
Output:  PpYyTtHhOoNn 

Let us understand the two scenarios of this problem

Scenario1:  If both the strings are of same length:

string1=input("Enter first string: ")
string2=input("Enter second string: ")
i,j=0,0 # object initialization using Tuple Unpacking
result=""
while i<len(string1) or j<len(string2):
	result=result+string1[i]+string2[j]
	i=i+1
	j=j+1
print("You entered first string : ",string1)
print("You entered second string : ",string2)
print("Final result after alternate merge: \n", result )

Scenario 2:  If the strings have different length:

string1=input("Enter first string: ")
string2=input("Enter second string: ")
i,j=0,0 # object initialization using Tuple Unpacking
result=""
while i<len(string1) or j<len(string2):
	if i<len(string1):
		result=result+string1[i]
		i=i+1
	if j<len(string2):
		result=result+string2[j]
		j=j+1
print("You entered first string: ",string1)
print("You entered second string: ",string2)
print("Final result after alternate merge: \n", result )

Print characters present at even and odd index separately

 1st Way :

1 2 3 4 5 6 7 8 9 10 11

string_data=input("Enter a string: ") print("Characters present at even index position: ") i=0 while i<len(string_data): print(string_data[i]) i=i+2 print("Characters present at odd index position: ") i=1 while i<len(string_data): print(string_data[i]) i=i+2

 2nd Way:

string_data=input("Enter a string: ")
print("Characters present at even index position: ")
print(string_data[::2]) # or
print(string_data[0::2])
print("Characters present at odd index position: ")
print(string_data[1::2])

Reverse internal content of every second word

 Sample Input: one two three four five six seven eight

Output: one owt three ruof five xis seven thgie

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

string_data=input("Enter a string: ") list1=string_data.split() print(list1) list2=[] i=0 while i<len(list1): if i%2==0: list2.append(list1[i]) else: list2.append(list1[i][::-1])# Reversing word and then adding to list2 i=i+1 print(list2) result=" ".join(list2) print("The string you entered:", string_data, sep="\n") print("The result after reversing order of words in the string: ", result, sep="\n")

Reverse the internal content of each word

 

 

 

Sample Input: Hello Python

Output: olleH nohtyP

 

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string_data=input("Enter a string: ") list1=string_data.split() print(list1) list2=[] for word in list1: list2.append(word[::-1]) # Reversing word and then adding to list2 print(list2) result=" ".join(list2) print("The string you entered:", string_data, sep="\n") print("The result after reversing order of words in the string: ", result, sep="\n")

 

Reverse order of words in a string

 

 

Sample Input: Hello everyone ! Welcome to MV's Code Guide

Output: Guide Code MV's to Welcome ! everyone Hello

Using Slice operator:

1 2 3 4 5 6 7 8

string_data=input("Enter a string: ") list1=string_data.split() #Using Slice Operator to reverse the items of list1 list2=list1[::-1] # Using join() to form a string from items of list2 result=" ".join(list2) print("The string you entered:", string_data, sep="\n") print("The result after reversing order of words in the string: ", result, sep="\n")

 Using While loop:

1 2 3 4 5 6 7 8 9 10 11 12

string_data=input("Enter a string: ") list1=string_data.split() print(list1) list2=[] i=len(list1)-1 while i>=0: list2.append(list1[i]) i=i-1 print(list2) result=" ".join(list2) print("The string you entered:", string_data, sep="\n") print("The result after reversing order of words in the string: ", result, sep="\n")

String Reversal

 Python program to reverse a string:

 

There are three ways to reverse a string in Python:

1st way: Using Slice Operator: 

(To learn about slice operator click here)

1 2 3 4

string_data=input("Enter data you want to reverse") result=string_data[::-1] print("The string data you entered is :", string_data) print("The reversed string is:", result)

  2nd way: Using reversed() function:

Python provides inbuilt function reversed()

It returns reversed object and you can use join() method of strings to get your required output form reversed object.

1 2 3 4 5 6 7

string_data=input("Enter data you want to reverse") reversed_object=reversed(string_data) print("The string data you entered is :", string_data) for character in reversed_object: print(character,end='') print() print(type(reversed_object))

3rd way : Using While loop:

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string_data=input("Enter data you want to reverse: ") result="" i=len(string_data)-1 while i>=0: result=result+string_data[i] i=i-1 print("The string data you entered is :", string_data) print("String data after reversal: ", result)