In this tutorial, we will be learning about how to get a range of characters in Python. Python, being a powerful and flexible programming language, provides various ways to get a range of characters from strings.
This process is also known as slicing. It’s a rather simplistic but extremely useful concept, essential to any kind of data manipulation in Python.
Step 1: Understanding Python String Indexing
In Python, strings are ordered sequences of characters, which can be accessed via indices. The index refers to the position of each character in the string. The indices for a string start at 0 for the first character, and move up by 1 each time.
For example, the string “PYTHON” has the ‘P’ at index 0, ‘Y’ at index 1, and so on.
Step 2: String Slicing in Python
To get a range of characters, we use the slice syntax in Python, which is the bracket notation []. The general form is [start:end] where the start index is inclusive, and the end index is exclusive.
For instance, if we need to get the first three characters from the string “PYTHON”, we can use the following code:
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text = "PYTHON" slice = text[0:3] print(slice) |
The output will be:
PYT
Step 3: Using Negative Indexing for Slicing
Python also supports negative indexing, where -1 represents the index of the last character in the string, -2 for the second last, and so on. This is very useful when you want to slice characters from the end of a string.
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text = "PYTHON" slice = text[-3:-1] print(slice) |
The output will be:
HO
Step 4: Omitting the Start or End Index
Python allows us to omit the start index or the end index (or both) when performing slicing. If omitted, Python takes the start index as 0 and the end index as the length of the string.
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text = "PYTHON" slice_start_omitted = text[:3] slice_end_omitted = text[3:] print(slice_start_omitted) print(slice_end_omitted) |
The output will be:
PYT HON
Full Code:
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text = "PYTHON" slice = text[0:3] print(slice) slice = text[-3:-1] print(slice) slice_start_omitted = text[:3] print(slice_start_omitted) slice_end_omitted = text[3:] print(slice_end_omitted) |
Conclusion
In this tutorial, we learned how to get a range of characters using Python slicing. We examined positive indexing, negative indexing, and the scenario of omitted indices. String slicing is an integral part of Python programming, especially when dealing with text data processing.
Keep practicing this feature as it has many applications in data manipulation tasks, notably in the fields of data analysis and machine learning.