# Python String Methods | Set 1 (find, rfind, startwith, endwith, islower, isupper, lower, upper, swapcase & title)

Last Updated : 16 Jun, 2022

Some of the string basics have been covered in the below articles
Strings Part-1
Strings Part-2
1. find(“string”, beg, end) :- This function is used to find the position of the substring within a string.It takes 3 arguments, substring , starting index( by default 0) and ending index( by default string length)

• It returns “-1 ” if string is not found in given range.
• It returns first occurrence of string if found.

2. rfind(“string”, beg, end) :- This function has the similar working as find(), but it returns the position of the last occurrence of string.

## Python

 `# Python code to demonstrate working of ` `# find() and rfind()` `str` `=` `"geeksforgeeks is for geeks"` `str2 ``=` `"geeks"`   `# using find() to find first occurrence of str2` `# returns 8` `print` `(``"The first occurrence of str2 is at : "``, end``=``"")` `print` `(``str``.find( str2, ``4``) )`   `# using rfind() to find last occurrence of str2` `# returns 21` `print` `(``"The last occurrence of str2 is at : "``, end``=``"")` `print` `( ``str``.rfind( str2, ``4``) )`

Output:

```The first occurrence of str2 is at : 8
The last occurrence of str2 is at : 21```

Time complexity : O(n)
Auxiliary Space : O(1)

3. startswith(“string”, beg, end) :- The purpose of this function is to return true if the function begins with mentioned string(prefix) else return false.
4. endswith(“string”, beg, end) :- The purpose of this function is to return true if the function ends with mentioned string(suffix) else return false.

## Python3

 `# Python code to demonstrate working of ` `# startswith() and endswith() ` `str` `=` `"geeks"` `str1 ``=` `"geeksforgeeksportal"`   `# using startswith() to find if str ` `# starts with str1 ` `if` `str1.startswith(``str``): ` `        ``print` `(``"str1 begins with : "` `+` `str``) ` `else` `: ``print` `(``"str1 does not begin with : "``+` `str``) `   `# using endswith() to find ` `# if str ends with str1 ` `if` `str1.endswith(``str``): ` `    ``print` `(``"str1 ends with : "` `+` `str``) ` `else` `: ` `    ``print` `(``"str1 does not end with : "` `+` `str``) `

Output:

```str1 begins with : geeks
str1 does not end with : geeks```

Time complexity : O(n)
Auxiliary Space : O(1)

5. islower(“string”) :- This function returns true if all the letters in the string are lower cased, otherwise false.
6. isupper(“string”) :- This function returns true if all the letters in the string are upper cased, otherwise false.

## Python3

 `# Python code to demonstrate working of ` `# isupper() and islower()` `str` `=` `"GeeksforGeeks"` `str1 ``=` `"geeks"`   `# checking if all characters in str are upper cased` `if` `str``.isupper() :` `    ``print` `(``"All characters in str are upper cased"``)` `else` `: ` `    ``print` `(``"All characters in str are not upper cased"``)`   `# checking if all characters in str1 are lower cased` `if` `str1.islower() :` `    ``print` `(``"All characters in str1 are lower cased"``)` `else` `: ` `    ``print` `(``"All characters in str1 are not lower cased"``)`

Output:

```All characters in str are not upper cased
All characters in str1 are lower cased```

Time complexity : O(n)
Auxiliary Space : O(1)

7. lower() :- This function returns the new string with all the letters converted into its lower case.
8. upper() :- This function returns the new string with all the letters converted into its upper case.
9. swapcase() :- This function is used to swap the cases of string i.e upper case is converted to lower case and vice versa.
10. title() :- This function converts the string to its title case i.e the first letter of every word of string is upper cased and else all are lower cased.

## Python3

 `# Python code to demonstrate working of ` `# upper(), lower(), swapcase() and title()` `str` `=` `"GeeksForGeeks is fOr GeeKs"`   `# Converting string into its lower case` `str1 ``=` `str``.lower();` `print` `(``" The lower case converted string is : "` `+` `str1)`   `# Converting string into its upper case` `str2 ``=` `str``.upper();` `print` `(``" The upper case converted string is : "` `+` `str2)`   `# Converting string into its swapped case` `str3 ``=` `str``.swapcase();` `print` `(``" The swap case converted string is : "` `+` `str3)`   `# Converting string into its title case` `str4 ``=` `str``.title();` `print` `(``" The title case converted string is : "` `+` `str4)`

Output:

``` The lower case converted string is : geeksforgeeks is for geeks
The upper case converted string is : GEEKSFORGEEKS IS FOR GEEKS
The swap case converted string is : gEEKSfORgEEKS IS FoR gEEkS
The title case converted string is : Geeksforgeeks Is For Geeks```

Time complexity : O(n)
Auxiliary Space : O(1)