In Python, when we work with lists of words or phrases, we often need to break them into smaller pieces, called substrings. A substring is a contiguous sequence of characters within a string. Creating a new list of substrings from a list of strings can be a common task in various applications. In this article, we will create a new list of substrings from a list of strings.

Create a New List of Substrings from the List of Strings

Below are some of the ways by which we can create a new list of substrings from the list of strings in Python:

Using List Comprehension

In this example, a list comprehension is employed to create a new list, `substring_list`, containing substrings extracted from each string in the `original_list`. The slicing notation `[s[1:4] for s in original_list]` extracts characters from index 1 to 3 (exclusive) from each string in the original list.

# Original list of strings
original_list = ["apple", "banana", "orange"]

# Using list comprehension to extract substrings
substring_list = [s[1:4] for s in original_list]

# Displaying the result
print(substring_list)

# Original list of strings

original_list = ["apple", "banana", "orange"]

​

# Using list comprehension to extract substrings

substring_list = [s[1:4] for s in original_list]

​

# Displaying the result

print(substring_list)

['ppl', 'ana', 'ran']

Using map() Function

In this example, a function `extract_substring` is defined to extract a substring from a given string `s`, and the `map()` function is used to apply this function to each element in the `original_list`. The result is a new list, `substring_list`, containing the extracted substrings, which is then printed.

# Original list of strings
original_list = ["apple", "banana", "orange"]

# Function to extract substring
def extract_substring(s):
    return s[1:4]

# Applying the function using map()
substring_list = list(map(extract_substring, original_list))

# Displaying the result
print(substring_list) 

# Original list of strings

original_list = ["apple", "banana", "orange"]

​

# Function to extract substring

def extract_substring(s):

    return s[1:4]

​

# Applying the function using map()

substring_list = list(map(extract_substring, original_list))

​

# Displaying the result

print(substring_list)

['ppl', 'ana', 'ran']

Using Lambda Function with map() Function

In this example, a lambda function is applied using the `map()` function to extract substrings `[1:4]` from each string in the `original_list`. The result is a new list, `substring_list`, containing the extracted substrings, which is then printed.

# Original list of strings
original_list = ["apple", "banana", "orange"]

# Applying a lambda function using map() for substring extraction
substring_list = list(map(lambda s: s[1:4], original_list))

# Displaying the result
print(substring_list)  # Output: ['ppl', 'ana', 'ran']

# Original list of strings

original_list = ["apple", "banana", "orange"]

​

# Applying a lambda function using map() for substring extraction

substring_list = list(map(lambda s: s[1:4], original_list))

​

# Displaying the result

print(substring_list)  # Output: ['ppl', 'ana', 'ran']

['ppl', 'ana', 'ran']

Using List Comprehension with Conditional Statements

In this example, a list comprehension with a conditional statement is employed to create a new list, `substring_list`. It extracts substrings `[1:4]` from strings in the `original_list` only if the length of the string is greater than or equal to 4; otherwise, the original string is retained. The resulting list is then printed.

# Original list of strings
original_list = ["apple", "banana", "orange"]

# Using list comprehension with conditional statements for substring extraction
substring_list = [s[1:4] if len(s) >= 4 else s for s in original_list]

# Displaying the result
print(substring_list)  # Output: ['ppl', 'ana', 'ran']

# Original list of strings

original_list = ["apple", "banana", "orange"]

​

# Using list comprehension with conditional statements for substring extraction

substring_list = [s[1:4] if len(s) >= 4 else s for s in original_list]

​

# Displaying the result

print(substring_list)  # Output: ['ppl', 'ana', 'ran']

['ppl', 'ana', 'ran']