You can return a range of characters by using the slice syntax.
Specify the start index and the end index, separated by a colon, to return a part of the string.
b = "Hello, World!"
print(b[2:5])
Slice From the Start
By leaving out the start index, the range will start at the first character:
b = "Hello, World!"
print(b[:5])
Slice To the End
By leaving out the end index, the range will go to the end:
b = "Hello, World!"
print(b[2:])
Negative Indexing
Use negative indexes to start the slice from the end of the string:
b = "Hello, World!"
print(b[-5:-2])
Upper Case
a = "Hello, World!"
print(a.upper())
Lower Case
a = "Hello, World!"
print(a.lower())
Remove Whitespace
Whitespace is the space before and/or after the actual text, and very often you want to remove this space.
a = " Hello, World! "
print(a.strip()) # returns "Hello, World!"
Replace String
a = "Hello, World!"
print(a.replace("H", "J"))
Split String
The split()
method returns a list where the text between the specified separator becomes the list items.
a = "Hello, World!"
print(a.split(",")) # returns ['Hello', ' World!']
String Concatenation
To concatenate, or combine, two strings you can use the + operator.
a = "Hello"
b = "World"
c = a + b
print(c)
a = "Hello"
b = "World"
c = a + " " + b
print(c)
String Format
As we learned in the Python Variables chapter, we cannot combine strings and numbers like this:
age = 36
txt = "My name is John, I am " + age
print(txt)
But we can combine strings and numbers by using the format()
method!
The format()
method takes the passed arguments, formats them, and places them in the string where the placeholders {}
are:
age = 36
txt = "My name is John, and I am {}"
print(txt.format(age))
The format() method takes unlimited number of arguments, and are placed into the respective placeholders:
quantity = 3
itemno = 567
price = 49.95
myorder = "I want {} pieces of item {} for {} dollars."
print(myorder.format(quantity, itemno, price))
You can use index numbers {0}
to be sure the arguments are placed in the correct placeholders:
quantity = 3
itemno = 567
price = 49.95
myorder = "I want to pay {2} dollars for {0} pieces of item {1}."
print(myorder.format(quantity, itemno, price))
Escape Character
To insert characters that are illegal in a string, use an escape character.
An escape character is a backslash \
followed by the character you want to insert.
An example of an illegal character is a double quote inside a string that is surrounded by double quotes:
txt = "We are the so-called "Vikings" from the north."
Escape Characters Other escape characters used in Python:
Code Result \' Single Quote \\ Backslash \n New Line \r Carriage Return \t Tab \b Backspace \f Form Feed \ooo Octal value \xhh Hex value
String Methods
Python has a set of built-in methods that you can use on strings.
Method Description capitalize() Converts the first character to upper case casefold() Converts string into lower case center() Returns a centered string count() Returns the number of times a specified value occurs in a string encode() Returns an encoded version of the string endswith() Returns true if the string ends with the specified value expandtabs() Sets the tab size of the string find() Searches the string for a specified value and returns the position of where it was found format() Formats specified values in a string format_map() Formats specified values in a string index() Searches the string for a specified value and returns the position of where it was found isalnum() Returns True if all characters in the string are alphanumeric isalpha() Returns True if all characters in the string are in the alphabet isascii() Returns True if all characters in the string are ascii characters isdecimal() Returns True if all characters in the string are decimals isdigit() Returns True if all characters in the string are digits isidentifier() Returns True if the string is an identifier islower() Returns True if all characters in the string are lower case isnumeric() Returns True if all characters in the string are numeric isprintable() Returns True if all characters in the string are printable isspace() Returns True if all characters in the string are whitespaces istitle() Returns True if the string follows the rules of a title isupper() Returns True if all characters in the string are upper case join() Joins the elements of an iterable to the end of the string ljust() Returns a left justified version of the string lower() Converts a string into lower case lstrip() Returns a left trim version of the string maketrans() Returns a translation table to be used in translations partition() Returns a tuple where the string is parted into three parts replace() Returns a string where a specified value is replaced with a specified value rfind() Searches the string for a specified value and returns the last position of where it was found rindex() Searches the string for a specified value and returns the last position of where it was found rjust() Returns a right justified version of the string rpartition() Returns a tuple where the string is parted into three parts rsplit() Splits the string at the specified separator, and returns a list rstrip() Returns a right trim version of the string split() Splits the string at the specified separator, and returns a list splitlines() Splits the string at line breaks and returns a list startswith() Returns true if the string starts with the specified value strip() Returns a trimmed version of the string swapcase() Swaps cases, lower case becomes upper case and vice versa title() Converts the first character of each word to upper case translate() Returns a translated string upper() Converts a string into upper case zfill() Fills the string with a specified number of 0 values at the beginning
Tags: Python Python Escape Character Python Modify Strings Python Slicing Strings String Concatenation String Format