This article entitle Python String is a continuation of the previous article entitled Python Number.
Python Strings are one of the most used and popular data types we can easily create a string by enclosing the characters in single or double quotes.
What is String in Python?
In Python, a string is an immutable data type that cannot be changed once they are already created since the strings is cannot be changed the only way to change it is to construct a new string.
Example
stringOne = 'Hello World By SOURCECODEHERO!' stringTwo = "Python Tutorial For True Heroes"
Accessing String Characters in Python
To access the values or individual characters in a string we can use three different ways negative indexing, indexing, and slicing.
Negative indexing in Python is very similar to a list which allows to index of the given format string representation.
Example
name = 'Glenn' # access 3th last element print(name[-3]) # "e"
Output
e
Indexing is one of the ways to treat a string as a list and simply use the index values.
Example
name = 'Glenn' # access 3th last element print(name[3]) # "n"
Output
n
The slicing operator ( : ) colon can be used to access a range of characters in a string.
Example
name = 'Glenn' # access character from 1st index to 3rd index print(name[1:3]) # "le"
Output
le
Take Note: In some instances that you want to access an index that is out of range or a number that uses other than an integer, we will get an error in Python.
Updating Strings in Python
In some instances where you want to update an existing string object, you can use the ‘update’ and reassign a variable and set a new string. You can create a value that is related to the previous value or else a totally different string together.
Example
stringOne = 'Hello Python!' print ("Updated String :- ", stringOne[:6] + 'Heroes')
Output
Updated String :- Hello Heroes
Multiline String in Python
To create a multiline string in Python we can simply use the triple single quotes (”’) or triple quotes (“””).
Example
# multiline string greetings = ''' If you want a free source code and tutorials sourcecodehero is always here for you ''' print(greetings)
Output
If you want a free source code and tutorials sourcecodehero is always here for you
String Operations in Python
There are many operations that can be used to perform with a string that can make it one of the most useful data types in Python.
To compare two strings we can simply use the == operator once the two strings are equal the operators will return true otherwise will return false.
Example
stringOne = "Hello, world!" stringTwo = "I love Python." stringThree = "Hello, world!" # compare stringOne and stringThree print(stringOne == stringTwo) # compare stringOne and stringThree print(stringOne == stringThree)
Output
False True
Join two or more strings in Python
To join two or more strings we can simply join it with a concatenate using a plus (+) operator.
Example
greetings = "Hi, " name = "Jack" # using + operator results = greetings + name print(results) # Output: Hi, Jack
Output
Hi, Jack
String Length in Python
To find the length of the string we can simply use the len() method.
Example
name = 'Glenn' # count length of name string print(len(name)) # Output: 5
Output
5
Iterate a string in Python
Using a for loop we can easily iterate a given template string.
Example
name = 'Glenn' # iterating through name string for iterate in name: print(iterate)
Output
G l e n n
String membership test in Python
Using the ( in ) keyword we can easily test once if the substring was exist within the string or none.
Example
print('r' in 'sourcecodehero') # True print('al' not in 'tutorial') #False
Output
True False
Python Escape Sequences
The following list is all escape sequences that are supported by Python
Escape Sequence | Description |
---|---|
\\ | Backslash |
\' | Single quote |
\" | Double quote |
\a | ASCII Bell |
\b | ASCII Backspace |
\f | ASCII Formfeed |
\n | ASCII Linefeed |
\r | ASCII Carriage Return |
\t | ASCII Horizontal Tab |
\v | ASCII Vertical Tab |
\ooo | A character with octal value ooo |
\xHH | A character with hexadecimal value HH |
An escape sequence is mostly used for escaping some of the whitespace characters that are present within the string. Supposed that we need to add both single quotes and double quotes within the string.
Example
words = "She said, "How are you?"" print(words) # throws error
Since the strings were represented by a double or a single quote, The Python compiler will read the “She said” as a string and the above program will result in an error.
In order to solve this type of error we will use the escape character ( \ ) to escape and run the program correctly.
# escape double quotes greetings = "She said, \"How's your day?\"" # escape single quotes greetings = 'She said, "How\'s your day?"' print(greetings)
Output
She said, "How's your day?"
String methods in Python
Aside from the mentioned above, there is still a number of string format methods that are present in Python. The following are some of the methods below.
Methods | Description |
---|---|
upper() | converts the string to uppercase |
lower() | converts the string to lowercase |
partition() | returns a tuple |
replace() | replaces substring inside |
find() | returns the index of first occurrence of substring |
rstrip() | removes trailing characters |
split() | splits string from left |
startswith() | checks if string starts with the specified string |
isnumeric() | checks numeric characters |
index() | returns index of substring |
String formatting or (f-Strings) can be used to print variables and values in an easy way.
Example
name = 'Glenn' country = 'Philippines' print(f'{name} is from {country}')
Output
Glenn is from Philippines
Summary
In summary, you have read about Python String. We also discussed in this article what is String in Python, accessing string characters, updating strings, multiline strings, string operations, joining two or more strings, string length, iterating a string, string membership test, escape sequences, and string methods.
I hope this article about String in Python programming language could help you a lot to continue pursuing learning this powerful programming language.
If you want to learn more check out my previous and latest articles for more career-changing articles.