String Index.

Chapter 3 — Text. So far we worked with numbers and structures. Now the string is the main character: a sequence of characters inside quotes.

Every character has an index. Counting starts at 0: the first character is text[0], the second is text[1]. A negative index counts from the end: text[-1] is the last character.

A slice takes part of the string: text[start:stop]. start is included, stop is not. For example "python"[0:3] gives "pyt". If you omit the end, the slice runs to the end of the string.

Mini example:

word = "code"
print(word[0])
print(word[-1])
print(word[1:3])

Common mistake: expecting text[1] to be the first character; or including stop in the result ([0:3] does not include index 3). Another mistake: text[100] on a short string — IndexError.

Today we only read by index and slice. Methods like upper/split come in later lessons.