These are methods not functions, so the syntax uses the ‘.’ after an object of type str. For example, use "hello".capitalize() not capitalize("hello"). There are many string methods – not all are listed here, and for some that are there are optional extra arguments that I do not document here.
capitalize() return type: str
Returns a version of the string with the initial letter capitalized.
count(substring) return type: int
Counts how many times ‘substring’ occurs in the string, then returns this count (which may be 0) as an integer.
find(substring) return type: int
Returns the index (position) of the first occurrence of ‘substring’ occurs in the string. If substring isn’t found, it returns -1.
isalpha() return type: bool
Returns True if all characters in the string are letters, otherwise returns False
isnumeric() return type: bool
Returns True if all characters in the string are digits, otherwise returns False
join(container) return type: string
The opposite of split. Join takes a container (e.g. a list, normally a list of strings) as an argument and joins all the elements together into a single string, using the object string as a separator. For example, ",".join(["goodbye", "cruel", "world"]) returns the string "goodbye,cruel,world".
lower() return type: str
Returns a copy of the string with all characters converted to lowercase.
replace(oldtext, newtext) return type: str
Returns a copy of the string in which all occurrences of the text oldtext are replaced with newtext.
split(split_on) return type: list (of strings)
Splits a string on the substring split_on into a list of strings. For example, "goodbye cruel world".split(" ") returns ["goodbye", "cruel", "world"]. split_on is normally done on a one-character string, but it doesn't have to be.
strip() return type: str
Returns a copy of the string with any whitespace characters (spaces, tabs, newlines) removed from both the start and end
upper() return type: str
Returns a copy of the string with all characters converted to uppercase.