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 CharactersOther 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
|