Slices support the third argument, which is the step value. Output: Code language: JSON / JSON with Comments ( json ) The step value To get the 'blue' and 'orange' elements from the colors list, you can combine the negative and positive bounds: colors = The following example uses the negative start and stop bounds to slice a list: colors = The slice object also accepts negative start and stop bounds. The following example returns an empty list: colors = īecause the start is 10, Python assigns the len(colors) to it. Since the stop bound is 100, Python uses the len(colors) for the stop bound. Output: Code language: JSON / JSON with Comments ( json ) The following example returns the entire list: colors = The start defaults to 0 and stop defaults to len(seq) when you don’t specify it. … Python uses len(seq) for the start or stop.īoth start and stop are optional. When start or stop is greater than the length of the sequence: len(seq) In other words, it returns all elements of the sequence at the index n where n satisfies the following expression: start <= n < stop The slice seq selects elements starting at the index start and stopping at the index stop (excluding the element at the index stop). Output: Code language: JSON / JSON with Comments ( json ) Python Slicing: start and stop bounds … you can use the slice object instead: colors = So instead of using the slicing notation: colors Code language: CSS ( css ) Print(s.start, s.stop) Code language: PHP ( php ) When you use the slicing notation: seq Code language: CSS ( css ) A slice is actually an object of the slice type. Therefore, it’s easier to visualize that the indexes are between the elements when you slice the sequence:Įverything in Python is an object including the slice. The slicing seq returns the elements starting at the index start up to the index stop - 1. For example: topic = 'Java' Code language: JavaScript ( javascript )Įrror: TypeError: 'str' object does not support item assignment Code language: JavaScript ( javascript ) If you attempt to use slicing to assign data to an immutable sequence, you’ll get an error. For example: topic = 'Python Slicing' # Extract data print(topic) Code language: PHP ( php ) However, you can use slicing to extract data from immutable sequences. Code language: JSON / JSON with Comments ( json ) Therefore, slicing only works with sequence types.įor mutable sequence types such as lists, you can use slicing to extract and assign data. So far you’ve learned about slicing such as list slicing. Summary: in this tutorial, you’ll learn about Python slicing and how to use it to extract data from and assign data to a sequence.
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