Python String Methods

Republished By Plato

Followers: 0

Python String Methods
Image by Author

In this blog, we will be reviewing Python’s built-in methods to operate on Strings. You can use these methods to perform boolean checks and replace or change the form of the string.

upper

The `upper()` method changes all lowercase alphabets into uppercase.

text = 'knoWledge dIsCoverY NuggETS' # Converting string to uppercase
new_string = text.upper()
print(f"Before: {text}nAfter: {new_string}n")

Before: knoWledge dIsCoverY NuggETS
After: KNOWLEDGE DISCOVERY NUGGETS

replace

The `replace()` method requires two arguments to replace all occurrences of a substring with another substring.

# Replacing the string
new_string = text.replace("knoWledge dIsCoverY ","KD")
print(f"Before: {text}nAfter: {new_string}n")

Before: knoWledge dIsCoverY NuggETS
After: KDNuggETS

find

The `find()` will search for a substring and if it is found, it will return the lowest index of the substring.

# Find the string
new_string = text.find("dIsCoverY")
print(f"The string is at {new_string} indexn")

The string is at 10 index

isnumeric

The `isnumeric()` method returns “True” if all of the characters in the string are numeric.

# Is the text numerical?
new_string = text.isnumeric()
print(f"Is the text numerical? {new_string}n") print(f"Is·the·text·numerical?·{new_string}n")
#·Is·the·text·numerical?
new_string·=·text.isnumeric()

Is the text numerical? False

Case Change

lower(): it changes all uppercase characters to lowercase.
capitalize(): it changes the first character of the string to uppercase.
upper(): it changes all lowercase characters to uppercase.
title(): it changes string to title case.
casefold(): it implements caseless string matching.
swapcase(): it changes all uppercase characters to lowercase and lowercase to uppercase.

Checks

startswith(): it returns “True” if the string starts with the given substring.
endswith(): it returns “True” if the string ends with the given substring.
isalnum(): it checks if all characters in the string are alphanumeric or not.
isalpha(): it checks if all characters in the string are alphabets or not.
isdecimal(): it checks if all characters in the string are decimal or not.
isdigit(): it checks if all characters in the string are digits or not.
isidentifier(): it checks if the string is a valid identifier or not.
islower(): it checks if all characters in the string are lowercase or not.
isnumeric(): it checks if all characters in the string are numeric or not.
isprintable(): it returns “True” if all characters in the string are printable or the string is empty
isspace(): it checks if all characters in the string are whitespace characters or not.
istitle(): it checks if all characters in the string are title case or not.
isupper(): it checks if all characters in the string are uppercase or not.

Split and Join

join(): it returns a concatenated string.
partition(): it splits the string on the first occurrence of the separator.
rpartition(): it splits the string into three parts.
rsplit(): it splits the string from the right using a specified separator.
splitlines(): it splits the lines at line boundaries.
split(): it splits the string using a specified separator.

Padding and Cleaning

center(): Pad the string with the specified character.
ljust(): It left aligned the string using the specified width.
rjust(): It right aligned the string using the specified width.
lstrip(): it removes the leading characters from the string.
rstrip(): it removes the trailing characters from the string.
strip(): it removes both leading and trailing characters from the string.
zfill(): it returns a copy of the string with ‘0’ characters padded to the left side of the string.

Find and Replace

encode(): it encodes the string using a specified encoding scheme.
find(): it returns the lowest index of the specified substring.
rfind(): it returns the heights index of the specified substring.
index(): it returns the position of the first occurrence of a substring in a string.
rindex(): it returns the highest index of the substring inside the string.
replace(): it requires two arguments to replace all occurrences of a substring with another substring.

Miscellaneous

count(): it counts the number of occurrences of a substring in the string.
expandtabs(): it specifies the amount of space to be substituted with the “t” symbol in the string.
maketrans(): it returns a translation table.
translate(): it changes the string using translation mappings.
format(): it formats the string for console printing.
format_map(): it formats specified values in a string using a dictionary.

Abid Ali Awan (@1abidaliawan) is a certified data scientist professional who loves building machine learning models. Currently, he is focusing on content creation and writing technical blogs on machine learning and data science technologies. Abid holds a Master’s degree in Technology Management and a bachelor’s degree in Telecommunication Engineering. His vision is to build an AI product using a graph neural network for students struggling with mental illness.