String Manipulation in Python

tech / programming / python

This post is a very easy warm-up. I included some tricks for string manipulation in Python. Popular methods like replace() are not included here because they are too popular!

Checking String Type

Using isX methods

Let’s get straight to the point:

"Hello".isalpha() # Returns whether all characters in the string are alphabetic
"1234xyz".isalnum() # Returns whether all characters in the string are alphanumeric
"1234".isdecimal() # Returns whether all characters in the string are decimals
" \n".isspace() # Returns whether all characters in the string are whitespaces
"Hello".istitle() # Returns whether the string follows the rules of a title

# all the above lines should return True

There are more isX methods. This type of method is extremely useful for validating user inputs etc.

Checking start and end

We use startswith() and endswith() to check the ___ and ___ of a string. If you can’t fill the blanks maybe you should reconsider your decision to learn coding.

"Hello world!".startswith("Hello") # Returns whether the string starts with the specified value
"Hello world!".endswith("world!") # Returns whether the string ends with the specified value

# Returns:
# True
# True

String Manipulation

Join and split

Although these are also very common methods, I’m still giving them an honorable mention.

print(', '.join(['a', 'b', 'c'])) # 'a, b, c'
print('abc'.split('b')) # ['a', 'c']
# split() by default splits by whitespaces
print('My name is Leon'.split()) # ['My', 'name', 'is', 'Leon']

join() adds a string to in between the elements of a list to make a new string, split() does the exact opposite by breaking down a string to a list.

Strip

By using strip(), lstrip(), and rstrip() we can remove certain parts of a string.

" Hello ".lstrip() # removes leading whitespaces -> "Hello "
"SSSHelloSSS".lstrip("S") # removes leading 'S' -> "HelloSSS"
"-Hello-".rstrip("-") # '-Hello'
"SPAMHelloSPAMSPAM".strip("SPAM") # 'Hello'

Justifying strings

We can justify strings using ljust() to the left, rjust() to the right, center() to center

print("Hello".ljust(10)) # justify the string to the left within 10 spaces (padding with 5 spaces to the right)
print("Hello".rjust(10)) # justify the string to the right within 10 spaces (padding with 5 spaces to the left)
print("Hello".ljust(10, '*')) # justify the string to the left within 10 spaces (padding with 5 '*' to the right)
print("Hello".center(11, '-')) # justify the string to the center within 11 spaces (padding with 3 '-' to the left and right)
'''
Output:
Hello     
     Hello
Hello*****
---Hello---
'''

Using Pyperclip to Copy/Paste

To use pyperclip, first install the library by running pip install pyperclip. (NOT paperclip!)

In the script, always remember to import pyperclip

import pyperclip
pyperclip.copy('Hello world!') # copy the string
# if copied elsewhere after the line above, the output would be different
print(pyperclip.paste()) # 'Hello world!'

---

That’s all. The code might look a bit messy because I was hesitating for every example whether I should include the print() function or not, only for the sake of showcasing the usage of the methods, I apologize for the confusion it might have caused.

You must continue the journey without me. - Master Oogway