String functions

Python contains many useful built-in functions and methods to accomplish common tasks.

len(str)

returns the length of the string (number of characters).

join

joins a list of strings with another string as a separator.

print(", ".join(["spam","eggs","ham"]))

spam, eggs, ham

replace

• replace(old, new) replaces all occurrences of old with new.

print("Hello Me".replace("Me", "Ham"))

Hello Ham

startswith and endswith

determine if there is a substring at the start and end of a string, respectively.

find and rfind

search for a substr in a larger str. returns the index or -1 if not found. rfind starts from the right end to search. (Use the in operator for boolean result)

print("Hello Me".find('lo'))
print("Hello Me".find('lop'))
print("Hello Me".rfind('lo'))
print("lo" in "Hello Me")

3
-1
3
True

lower and upper

To change the case of a string, you can use lower and upper. - upper() converts the string to uppercase. - lower() converts the string to lowercase.

split

is the opposite of join turning a string with a certain separator into a list.

print("spam, eggs, ham".split(", "))

['spam', 'eggs', 'ham']

count

count(str) returns how many times the str substring appears in the given string.

print("Me Hello Me".count("Me"))
print("Me Hello Me".count("Meh"))

2
0