Welcome to our journey into Python strings! Today, we will delve into string operations, such as concatenation and slicing, and explore a variety of essential built-in string methods available in Python. By the end of your journey, you will have mastered these operations.
In Python, a String
is a sequence of characters. You can define them using single ('
), double ("
), or triple ('''
or """
) quotes for multiline strings:
Python1str1 = "Hello, Python!" 2str2 = 'Strings are fun.' 3str3 = """This is a 4Multiline 5String."""
Like lists, strings in Python have indices that start at 0.
Concatenation links strings together, much like joining links in a chain. Python uses the '+'
and '+='
operators for concatenation:
Python1str1 = 'Hello' 2str2 = 'World' 3merged_str = str1 + ', ' + str2 + '!' 4merged_str += ' See?' 5 6print(merged_str) # prints "Hello, World! See?"
Note: The '+'
operator is used only to join strings.
Slicing in Python is akin to slicing a loaf of bread — you take a piece from the whole. The syntax is pretty simple: str[start:end]
that takes a slice from start
to end,
with start
inclusive and end
exclusive. For example:
Python1message = 'Python Programming is fun!' 2slice_message = message[7:18] # Includes characters on positions 7, 8, ..., 17 3 4print(slice_message) # Prints 'Programming'
Python is equipped with various string methods, such as:
str.upper()
- converts all string letters to uppercase.str.lower()
- converts all string letters to lowercase.str.replace(from, to)
- replaces all occurrences offrom
toto
.str.index(sub)
- searches the index of the first occurrence of the provided substringsub
.str.join(e1, e2, ...)
- joins all provided stringse1
,e2
, ... with a provided separatorstr
.str.split(separator)
- splits the provided string into multiple parts by the providedseparator
.len(str)
- returns the length of the stringstr
.str * <number>
- repeats thestr
multiple times (number
times).
Here's an example of how they work:
Python1text = "Hello, World!" 2 3print(text.upper()) # prints "HELLO, WORLD!" 4print(text.lower()) # prints "hello, world!" 5print(text.replace('Hello', 'Hi')) # prints "Hi, World!" 6print(text.index('World')) # prints 7 7print(', '.join(['Hello', 'World', '!', 'How', 'are', 'you', '?'])) # prints "Hello, World, !, How, are, you, ?" 8print(text.split(", ")) # prints ["Hello", "World!"] 9print(len(text)) # prints 13 10print(text * 3) # prints "Hello, World!Hello, World!Hello, World!"
Python recognizes special escape sequences, such as \n
(newline), \t
(tab), and \\
(backslash). Here's a quick demonstration:
Python1str_with_escape_sequences = "Hello\nWorld!\tEnjoy Python Programming.\\" 2print(str_with_escape_sequences) 3""" 4Prints: 5Hello 6World! Enjoy Python Programming.\ 7"""
The message appears on two lines because \n
introduces a new line. \t
adds a tab space, and to print a single backslash, we use \\
.
Fantastic job! You've tackled Python string operations, learned about a variety of essential methods, and got acquainted with Python's special escape sequences. Practicing these will surely enhance your Python skills. Prepare for upcoming lessons on string formatting and interpolation. Onward!