Python String Format
Python String Methods
Python provides a variety of built-in string methods that allow you to manipulate and format strings in many ways. Each method returns a new string; the original string remains unchanged.
Here’s an overview of some common string methods:
1. capitalize()
Converts the first character of the string to uppercase.
python
1text = "hello world"
2print(text.capitalize()) # Output: "Hello world"
2. casefold()
Converts the string to lowercase, more aggressive than lower()
, useful for case-insensitive comparisons.
python
1text = "HELLO"
2print(text.casefold()) # Output: "hello"
3. center()
Centers the string, padding it with spaces or a specified character.
python
1text = "Hello"
2print(text.center(10, '*')) # Output: "**Hello***"
4. count()
Counts how many times a substring appears in a string.
python
1text = "banana"
2print(text.count('a')) # Output: 3
5. encode()
Encodes the string using the specified encoding (default is UTF-8).
python
1text = "Hello"
2print(text.encode()) # Output: b'Hello' (in bytes)
6. endswith()
Checks if the string ends with a specified suffix.
python
1text = "hello.txt"
2print(text.endswith('.txt')) # Output: True
7. find()
Finds the first occurrence of a substring and returns its position. Returns -1
if not found.
python
1text = "Hello World"
2print(text.find("World")) # Output: 6
8. format()
Inserts variables into a string using placeholders.
python
1name = "John"
2age = 30
3print("My name is {} and I am {} years old.".format(name, age)) # Output: My name is John and I am 30 years old.
9. isalnum()
Returns True
if the string consists only of alphanumeric characters (letters and numbers).
python
1text = "Hello123"
2print(text.isalnum()) # Output: True
10. isalpha()
Returns True
if the string consists only of alphabetic characters.
python
1text = "Hello"
2print(text.isalpha()) # Output: True
11. islower()
Checks if all characters in the string are lowercase.
python
1text = "hello"
2print(text.islower()) # Output: True
12. join()
Joins elements of an iterable (such as a list) into a single string, with a specified separator.
python
1list_of_words = ['Hello', 'World']
2print(" ".join(list_of_words)) # Output: "Hello World"
13. replace()
Replaces occurrences of a substring with another string.
python
1text = "Hello World"
2print(text.replace("World", "Universe")) # Output: "Hello Universe"
14. split()
Splits the string at the specified separator and returns a list.
python
1text = "apple,banana,grape"
2print(text.split(',')) # Output: ['apple', 'banana', 'grape']
15. strip()
Removes leading and trailing whitespace or specified characters.
python
1text = " Hello World "
2print(text.strip()) # Output: "Hello World"
16. upper()
Converts the string to uppercase.
python
1text = "hello"
2print(text.upper()) # Output: "HELLO"
17. title()
Converts the first character of each word to uppercase.
python
1text = "hello world"
2print(text.title()) # Output: "Hello World"
18. zfill()
Fills the string with leading zeros until it reaches a specified length.
python
1text = "42"
2print(text.zfill(5)) # Output: "00042"