What is split() in Python?

Christina 82 Published: 06/08/2024

What is split() in Python?

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In Python, the split() function is used to divide a string into multiple parts based on a specified delimiter or pattern. It's a powerful and versatile function that can be used in a wide range of applications.

The basic syntax of the split() function is as follows:

string.split(separator, maxsplit)

Where:

string is the original string you want to split.

separator is the delimiter or pattern you want to use to divide the string. This can be a single character (e.g., a space), a sequence of characters (e.g., a comma and space), or even a regular expression. maxsplit is an optional parameter that specifies the maximum number of splits to perform. If this value is exceeded, only that many splits are performed.

When you call split() on a string, it returns a list of substrings, where each substring corresponds to one of the original parts of the string separated by the delimiter.

Here's an example:

my_string = "hello,world,python"

parts = my_string.split(",")


print(parts)  # Output: ['hello', 'world', 'python']

In this case, we're splitting the string my_string on commas (,) and getting a list of three substrings: "hello", "world", and "python".

You can also use regular expressions as your separator. For example:

import re

text = "I love 3.14 more than 2.71"


parts = re.split(r"s*([0-9]+.?[0-9]|S+)s", text)


print(parts)  # Output: ['I', 'love', '3.14', 'more', 'than', '2.71']

Here, we're using the regular expression s*([0-9]+.?[0-9]*|S+)s* to match any sequence of digits followed by a decimal point (e.g., 3.14) or any non-space character (e.g., I, love). The s* part matches zero or more whitespace characters, and the parentheses around the pattern capture it as a group.

The split() function is very versatile and can be used in many creative ways. For instance:

You can split a string based on newline characters (n) to process text files. You can use regular expressions to extract specific patterns from large datasets. You can join multiple strings together using the join() method.

Overall, the split() function is an essential tool in any Python programmer's toolkit.

Python split regex

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Python provides several ways to split strings using regular expressions (regex). Here are a few examples:

1. re.split()

The re module is part of Python's standard library, and it provides the split() function. This function takes two arguments: the regex pattern to use as the delimiter, and the string to split.

For example:

import re

my_string = "hello,world,goodbye"


splitted = re.split(",", my_string)


print(splitted)  # Output: ['hello', 'world', 'goodbye']

2. str.split()

The str class in Python also has a split() method that can be used to split strings using regex.

For example:

my_string = "hello,world,goodbye"

splitted = my_string.split(",")


print(splitted)  # Output: ['hello', 'world', 'goodbye']

3. pandas.DataFrame.str.split()

If you're working with Pandas DataFrames and need to split strings, the str accessor has a split() method that accepts regex patterns.

For example:

import pandas as pd

data = {"words": ["hello,world,goodbye", "foo,bar,baz"]}


df = pd.DataFrame(data)


splitted = df["words"].str.split(",", expand=True)


print(splitted)  # Output: [['hello', 'world', 'goodbye'], ['foo', 'bar', 'baz']]

Some common regex patterns for splitting strings

Comma-delimited strings: "," or ",s*" (the latter includes whitespace after commas) Space-delimited strings: " ", "[s]+" Tabs-delimited strings: t Newline-delimited strings: n or "n"

Remember that when using regex patterns, you'll need to escape any special characters (like backslashes or parentheses) and consider whether your pattern should be greedy or not (by default, most regex patterns are greedy).

I hope this helps! Let me know if you have any specific questions about splitting strings with Python.

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