Take Parts with Slices

Indexing retrieves one character. A slice retrieves a sequence of characters as a new string.

word = "planet"
beginning = word[0:3]
print(beginning)

The output is pla.

Start included, stop excluded

A basic slice has two indexes separated by a colon:

text[start:stop]

The start index is included. The stop index is not included.

For word[0:3], Python takes indexes 0, 1, and 2. It stops before index 3.

This rule may feel unusual at first, but it has useful consequences. The number of characters in word[0:3] is 3 - 0, which is three.

Leave out an endpoint

Leave out the start to slice from the beginning:

print(word[:3])

Leave out the stop to slice through the end:

print(word[3:])

These print pla and net.

You can use negative indexes in slices too:

print(word[-3:])

This takes the final three characters: net.

Slices are forgiving

An individual index outside a string reports IndexError. A slice can stop beyond the end without failing:

print(word[:100])

Python returns all available characters. This difference is useful, but you should still choose slice boundaries that communicate your intention.

text = "notebook"
print(text[4:])

Split a course title

The starter string is:

Python Fundamentals

Use two slices:

• assign Python to language;

• assign Fundamentals to level.

Do not type those finished strings as literal answers. Derive them from course with slice notation.

The output must be:

Language: Python
Level: Fundamentals