Python program to split string into multiple substrings

In Python, we can split a string into substrings using the split() method. The split() method is one of the built-in Python string methods that splits a string into a list of substrings based on a specified delimiter. In this article, we will learn how to split a string into substrings with the help of examples.

Split string into substrings

Method 1: Use the split() method

The split() method is a built-in method of strings in Python, which splits a string into a list of substrings based on the specified delimiter. The delimiter can be any character or string that separates substrings. The split() method takes one parameter, the separator. If no delimiter is specified, it will split the string into individual characters.

Example: Split based on space and comma delimiters

In the following example, we will split the string using space delimiter. We use the split() method and pass the space delimiter to split the string based on spaces.

string = "Hello World"
substrings = string.split()
print(substrings)

string1 = "apple,banana,orange"
substrings = string1.split(",")
print(substrings)

Output

['Hello', 'World']
['apple', 'banana', 'orange']

Example: Split using regular expressions

In the following example, we use the split() function from the regular expression module to split the string "23-456-7890" into three substrings using dash and space delimiters.

import re

string = "123-456-7890"
substrings = re.split("-|\s", string)
print(substrings)

Output

['123', '456', '7890']

Method 2: Use list comprehension

List comprehensions are a concise way to create lists in Python. It allows you to create a new list based on an existing list or other iterable object, while also applying filters and performing transformations on the iterable's elements.

grammar

new_list = [expression for item in iterable if condition]

where "expression" is the transformation or operation to be performed on each element of the iterable, "item" is the element currently being processed, "iterable" is the source of the element, and "condition" is an optional filter A condition that determines whether an element is included in the result list.

Example

In the example below, we start with a string called "sentence", which contains a series of words separated by spaces. We use the split() method to split the string into a list of words and then use a list comprehension to create a new list called "words" that contains each word from the original string.

sentence = "The quick brown fox jumps over the lazy dog"
words = [word for word in sentence.split()]
print(words)

Output

['The', 'quick', 'brown', 'fox', 'jumps', 'over', 'the', 'lazy', 'dog']

Method 3: Use partition() method

partition() method is a built-in method of strings in Python, which splits the string into three parts based on the specified delimiter. It returns a tuple containing the left part of the string before the delimiter, the delimiter itself, and the right part of the string after the delimiter. If the delimiter is not found in the string, the method returns a tuple containing the original string, followed by two empty strings.

grammar

string.partition(delimiter)

Here, string is the string you want to split, and separator is the separator by which you want the partition function to split the string.

Example

In the following example, we use the partition() method to split the string "Hello World!" into three parts according to the space delimiter. The resulting tuple contains the left part "Hello", the separator "", and the right part "World!".

string = "Hello World!"
parts = string.partition(" ")
print(parts)

Output

('Hello', ' ', 'World!')

Method 4: Use the splitlines() function

The splitlines() method is a built-in method of strings in Python, which splits the string into a list of lines based on the newline character "\n". If the string does not contain any newlines, returns a list containing the original string as its only element.

grammar

string.splitlines()

Here, splitlines() takes no parameters and always splits the string based on newlines.

Example

In the following example, we use the splitlines() method to split the string "Line 1\nLine 2\nLine 3" into a list of lines. The resulting list contains three elements, one for each line in the original string.

string = "Line 1\nLine 2\nLine 3"
lines = string.splitlines()
print(lines)

Output

['Line 1', 'Line 2', 'Line 3']

Method 5: Use re.findall() method

re.findall() method is a function in the re module in Python that searches a string for all occurrences of a specified regular expression pattern and returns a list of all matches. Regular expression patterns can contain a variety of characters representing different types of characters or sequences, allowing complex pattern matching and extraction of specific parts of a string.

grammar

re.findall(regular_expression, string)

Here, the re.findall() method uses a regular expression to find occurrences of matching words in a string, which is also passed to the findall() function.

Example

In the following example, we use the re.findall() method to search for all occurrences of the regular expression pattern \b\w{5}\b in a string. This pattern matches any sequence of five word characters (letters, numbers, or underscores) surrounded by a word boundary (that is, the beginning or end of a word). The re.findall() method returns a list of all matches found in a string.

import re

string = "The quick brown fox jumps over the lazy dog"
matches = re.findall(r"\b\w{5}\b", string)
print(matches)

输出

['quick', 'brown', 'jumps']

结论

在本文中，我们讨论了如何在 Python 中使用 split() 函数、使用列表理解、使用分区方法、使用 splitline 方法以及使用 re.findall() 将字符串拆分为多个子字符串方法。 split() 函数采用分隔符作为参数。然后根据该分隔符分割字符串。 splitline 方法始终根据新行分隔符分割字符串。我们可以使用本文中介绍的任何方法，具体取决于我们想要执行的拆分类型。

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