Strings in Python

Creating Strings in Python

Single Line Strings

A string in Python is surrounded by either single quotation marks or double quotation marks. E.g., 'Coding Ninjas' is the same as "Coding Ninjas."

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# Creating and printing strings with single quotation marks.
string1 = 'Hello Ninjas'
print(string1)

# Creating strings with double quotation marks.
string2 = "Welcome to Coding Ninjas"
print(string2)

# Printing directly.
print('Hello Ninjas')
print("Welcome to Coding Ninjas")

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Output:

Multi-Line Strings

You can use three quotes to declare a multi-line String in Python.

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# Creating and printing multi-line strings with triple quotation marks.

 

string1 = '''Hello Ninjas,
Welcome to Coding Ninjas'''


print(string1)

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Output:

Check this out: Fibonacci Series in Python

Accessing characters of the String

Accessing Single Character

Since strings are like arrays, individual characters can be accessed using Indexing. The index must be an integer, and it starts from 0. 

Python also supports negative Indexing. The index value of -1 denotes the last item, the index of -2 the second last item, and so on. 

Trying to access a character outside the index range will result in an IndexError.
 

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string = "Coding Ninjas"
print("Original String: ")
print(string)

# Printing 1st character.
print("\nFirst character of the string is: ")
print(string[0])

# Printing the last character.
print("\nLast character of the string is: ")
print(string[-1])

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Output:

You can practice by yourself with the help of online python compiler for better understanding.

Accessing Multiple Characters: Slicing

The slicing method is used to access a range of characters in the String. A Slicing operator is used to slice a String (colon).

For example, 

String = “Coding Ninjas”

To print the characters odi of Coding Ninjas, 

we have to use: print(String[1:4]). 

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Python

string = "Coding Ninjas"
print("Original String: ")
print(string)

# Printing odi.
print("\nPrinting odi")
print(string[1:4])

# Printing characters between 2rd to 10th index.
print("\nPrinting characters between 2rd to 10th index:")
print(string[2:10])

# Printing characters between 3rd and the last character.
print("\nPrinting characters between 3rd and the last character:")
print(string[2:-1])

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Output:

String Length

Python provides the len() method to determine the length of a string.

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Python

string = "Coding Ninjas"
print("Original String: ")
print(string)

print("\nLength of the string 'Coding Ninjas' is: ")
print(len(string))

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Output:

Looping Through a String

Since strings are arrays, we can use a for loop to traverse through the characters in a string.

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Python

string = "Ninjas"
print("Original String: ")
print(string)

for x in string:
  print(x)

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Output:

Deletion in a String

The deletion of characters from a string is not allowed in Python. This will result in an error since the deletion of an item from String are is not supported. However, the entire String can be deleted with the built-in del Keyword.

Deleting a character

For example, deleting a character with index 2 from string "Coding Ninjas".

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Python

string = "Coding Ninjas"
print("Original String: ")
print(string)

del(string[2])
print(string)

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Output

Deleting an entire string:

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Python

string = "Coding Ninjas"
print("Original String: ")
print(string)

del(string)
print(string)

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Output:

Updation in a String

The updation of characters from a string is not allowed in Python. This will result in an error since the updation of an item from String are is not supported. Since strings are immutable, elements of a String cannot be modified after being assigned. Only new strings can be reassigned to the same name.

Updating a character in the string.

For example, updating a character with index 2 to ‘a’.

• Python

Python

string = "Coding Ninjas"
print("Original String: ")
print(string)

string[2] = 'a'
print(string)

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Output:

Updating an entire string:

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Python

string = "Coding Ninjas"
print("Original String: ")
print(string)

print("\nModified String: ")
string = 'Welcome Ninjas'
print(string)

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Output:

Repeat a String

Use the * symbol to repeat a string.

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Python

string = 'Coding'
string = string * 3
print(string)

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Output:

Also see, Python Filter Function

Formatting of Strings

Python also provides the format() function, a very versatile and powerful tool for formatting Strings. To set the order, the Format method in String uses curly braces {} as placeholders that can hold arguments based on position or keyword.

Syntax:

For example,

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name = ["John", "Aarti", "Rahul", "Karan"]
age = [20, 22, 21, 25]

for i in range(4):
  print("Hi, My name is {var1} and I am {var2} years old.".format( var1 = name[i], var2 = age[i]))

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Output:

Check out Escape Sequence in Python

Frequently Asked Questions

What is string data in Python?

String data in Python represents sequences of characters enclosed in quotes, used to handle and manipulate text in various ways.

Why use strings in Python?

Strings in Python are essential for text manipulation, data input/output, and communication between users and programs, making them vital for most applications.

Why is it called string?

It's called "string" because it represents a sequence of characters linked together, similar to how beads are strung on a thread.

Conclusion

In this article, we learned about Strings in Python. We also learned about 

• Accessing the characters in the string.
• Looping in a string.
• Calculating the length of a string.
• Deletion/Updation in the string.
• Formatting in the string.

Click here to learn about String Manipulation in Python.
Check out this article - String slicing in Python

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Recommended problems -

• Find the Shortest Substring in a String
• Subsequence of a String
• Beautiful String

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