Some of the string basics have been covered in the below articles
Strings Part-1
Strings Part-2
The important string methods will be discussed in this article
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 = "neveropen is for Lazyroar"str2 = "Lazyroar"# using find() to find first occurrence of str2# returns 8print ("The first occurrence of str2 is at : ", end="")print (str.find( str2, 4) )# using rfind() to find last occurrence of str2# returns 21print ("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 = "Lazyroar"str1 = "neveropenportal"# using startswith() to find if str# starts with str1if str1.startswith(str): print ("str1 begins with : " + str)else : print ("str1 does not begin with : "+ str)# using endswith() to find# if str ends with str1if str1.endswith(str): print ("str1 ends with : " + str)else : print ("str1 does not end with : " + str) |
Output:
str1 begins with : Lazyroar str1 does not end with : Lazyroar
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 = "Lazyroar"str1 = "Lazyroar"# checking if all characters in str are upper casedif 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 casedif 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 casestr1 = str.lower();print (" The lower case converted string is : " + str1)# Converting string into its upper casestr2 = str.upper();print (" The upper case converted string is : " + str2)# Converting string into its swapped casestr3 = str.swapcase();print (" The swap case converted string is : " + str3)# Converting string into its title casestr4 = str.title();print (" The title case converted string is : " + str4) |
Output:
The lower case converted string is : neveropen is for Lazyroar 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 : GeeksforLazyroar Is For Geeks
Time complexity : O(n)
Auxiliary Space : O(1)
