How to Get the First N Characters of a String in Python [6 Ways]

Are you looking to extract the first n characters of a string in Python? This Python tutorial will explore 6 different methods and techniques to “get the first n characters of a string in Python” with some practical and realistic examples.

Extracting the first N characters of a string in Python is a common operation in text processing and data manipulation tasks. Extracting a specific string portion can be crucial for working with user input, file contents, or database records.

These are the 6 different approaches to get the first n characters in Python.

  1. using string slicing
  2. using negative indexing in slicing
  3. using for loop
  4. using a while loop
  5. using regular expression
  6. using join() method

How to get the first n characters of a string in Python using string slicing

We will use string slicing in Python, which allows us to extract substrings by specifying a start and end index. To get the first n characters of a string, we can slice the string from index 0 to N.

Consider the following example to get the first n characters of a string in Python.

Code:

text = "The Statue of Liberty stands tall in New York Harbor."
n = int(input("Enter range : "))
first_n_characters = text[:n] 
print(f"First {n} characters:", first_n_characters)

In this code, text[:13] extracts the substring from index 0 to 12 (10 characters) from the text string.

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Output

Enter range : 13 
First 13 characters: The Statue of

Attached is a screenshot of my Python code executed in Visual Studio.

How to Get the First N Characters of a String in Python

Get the first n characters of a string in Python by giving negative indexing

We are using negative indexing in slicing to extract the first n characters of a string by counting characters from the end of the string.

Here’s a simple example to get the first n characters of a string in Python.

Code:

city = "Los Angeles"
n = int(input("Enter range : "))
first_n_chars = city[-len(city) : -len(city)+(n)]
print(f"First {n} characters:", first_n_chars)

In this code, we are taking -len(city) to target the first character of the string and giving the endpoint as -len(city)+(n) to extract the letters in the string according to user input.

Output

Enter range : 3
First 3 characters: Los

Here’s a screenshot showcasing my Python code in Visual Studio.

Get the first N characters of a String in Python

How to get the first N characters in a string using a for loop in Python

Using the for loop, we can iterate over the string and concatenate characters until we reach the desired length of N. For loop offers flexibility for dynamic conditions and is suitable for scenarios with more complex extraction logic.

Here’s an example of how you can use for loop to get the first n characters of a string in Python

Code:

state = "California"
n = int(input("Enter the range : "))
first_n_characters = ''

for char in state:
    if len(first_n_characters) < n:
        first_n_characters += char
    else:
        break
print(f"First {n} characters:", first_n_characters)

This code iterates over each character of the state string, appending them to first_five_chars until its length reaches 5.

Output

Enter the range : 5
First 5 characters: Calif

Included is a screenshot displaying my Python code from Visual Studio.

How to display the first few characters of a string in Python

Extract the first N letters in Python using a while loop

We can also use a while loop to iterate over every character to extract the first N characters of a string until the desired length is achieved. It provides flexibility for handling strings of varying lengths.

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Presented below is a simple example to get the first n characters of a string in Python.

Code:

text = "The Empire State Building is an iconic landmark in New York City."
first_n_chars = ''
index = 0
N = int(input("Enter the range : "))

while len(first_n_chars) < N and index < len(text):
    first_n_chars += text[index]
    index += 1
print("First", N, "characters:", first_n_chars)

In this example, A while loop is initialized to iterate until the length of first_n_chars reaches N or the end of the string text is reached.

while len(first_n_chars) < N and index < len(text):
    first_n_chars += text[index]
    index += 1

Within each iteration, the character at the current text index is appended to first_n_chars, and the index is incremented.

Output

Enter the range : 10
First 10 characters: The Empire

Here’s a screenshot of my Python code running in Visual Studio.

Get first N characters in python

Get the first N letters in Python using regular expression

The re.match() is a built-in function of the re module in Python that searches for the specified pattern at the beginning of the string text. The group() method retrieves the matched substring if a match is found.

Observe an example of using regex to get the first n characters of a string in Python.

Code:


import re

n = int(input("Enter range: "))
text = "The Grand Canyon is a natural wonder."
first_n_chars = rematch(r'.{%d}' % n, text).group()
print(f"First {n} characters:", first_n_chars)

In this code, we’ve used a regular expression pattern r’.{%d}’ % n, where the user-input value of n replaces %d, and the code matches the first n characters of the string text in Python.

Output

Enter range: 9
First 9 characters: The Grand

Attached is a screenshot of my Python code to get the first n characters of a string in Python.

get first n letters in python

Get first N characters from a string in Python using the join() method

We can use str.join() to join the elements of iterables in Python, and we can use it with the list comprehension to get the first n characters of a Python string.

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Let’s see an example of using str.join() method of Python to get the first n characters of a string in Python.

Code:

text = "The Golden Gate Bridge spans the Golden Gate Strait."
n = int(input("Enter the range : "))
first_n_chars = ''.join(text[i] for i in range(n))
print(f"First {n} characters:", first_n_chars)

In the above code, we’ve used the join() method with list comprehension to create a list of extracted characters according to user input range and concatenate all the characters into a single string by using the join() method in Python.

''.join(text[i] for i in range(n))

Output

Enter the range : 7
First 7 characters: The Gol

Here’s a screenshot of my Python code executed in Visual Studio.

extract first n letters in python

Conclusion

This article explains how to get the first N characters of a string in Python through multiple methods, each offering its unique advantages. We explored six methods or techniques: string slicing, negative indexing, loops (both for and while), regular expressions, and the join() method.

Understanding and utilizing these methods helps you efficiently manipulate text data in various applications.

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