Strings

String is a sequence of symbols. All of the symbols can be accessed via their indexes starting from 0.

Indexes

Let's say we have the string "computer". It's structure is the following:

So if we need to print the first letter (c) and the 3rd letter (m), we do:

word = "computer" print(word[0], word[2])

Output:

c m

Length

Length is the count of the symbols contained in a string.

It's accessed via the len function.

Example:

word = "Hello!" print(len(word))

Output:

6

Via len we can access the last symbol of a string.

Example:

str = "The quick brown fox jumps over the lazy dog!" print(str[len(str) - 1])

Output:

!

Access outside of bounds

Accessing string outside of it's bounds results in exception.

Let's look the following example:

str = "Phone" str[5]

The string has indexes from 0 to 4. Accessing index outside of that bound (in this case 5) causes exception.

Contains

We can check if string is contained in a string via the in operator.

Examples:

print('m' in 'simple') print('si' in 'simple') print('z' in 'simple') print('S' in 'simple')

Output:

True True False False

in can be used to check if single or multiple symbols are contained in string.

If a negative statment is necessary, then not in needs to be used.

Examples:

print('*' not in 'sky') print('k' not in 'sky')

Output:

True False

String iteration

All symbols of a string can be iterated via for loop.

Let's print all letters of a word that are not vowels:

word = 'composure' for letter in word: if letter not in 'aeiou': print(letter)

Output:

c m p s r

In this case letter not in 'aeiou' means that letter is a symbol that's not a vowel letter.