Strings are Objects

Strings are objects in Python which means that there is a set of built-in functions that you can use to manipulate strings. You use dot-notation to invoke the functions on a string object such as sentence.lower(). The function lower() returns a new string with all of the characters in the original string set to lowercase. The function capitalize() will return a new string with the first letter of the string capitalized.

Getting Part of a String

A string has characters in a sequence. Each character is at a position or index which starts with 0 as shown below. An index is a number associated with a position in a collection of values like a string.

a string with the position (index) shown above each character

Figure 1: A string with the position (index) shown above each character

A slice is a way to get part of a string. One way to use a slice is to do stringName[num]`. This will return a new string with just the character at that position in the string.

a string with the position (index) shown above each character

Figure 2: A string with the position (index) shown above each character

A slice with two values separated with a : between them returns a new string with the characters from the given start position to the one before the given end position.

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Some Other String Functions

The len(string) function takes a string as input and returns the number of characters in the string including spaces.

The find(string) function takes a string as input and returns the index where that string is found in the current string. If the string isn’t found it returns -1.

Note

The find function will return the first position it finds the given string in. Notice that above it printed 2 which means it found the “is” in “This” first.

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