STRING METHODS

What is string methos?

• These are the methods which we can apply only on string data.
• In python all the methods are called as attributes. If there is any error in any method, it shows Attribute error.

Syntax: variable name. method name ()

1. Upper():

• It is used to convert all the lower-case characters into upper-case characters and ignore remaining characters.
• It will not replace an existing string; it creates a new string.

Syntax: variable name. upper ()

Ex:

2. Lower():

• It is used to convert all the upper-case characters into lower-case characters and ignore remaining characters.
• It will not replace an existing string; it creates a new string.

Syntax: variable name. lower ()

Ex:

3. Swapcase():

• It converts lower case characters to upper case or upper-case characters to lower case and remaining characters will be ignored.
• It will not replace an existing string; it returns a new string.

Syntax: variable name. swapcase ()

Ex:

4. Capitalize():

• It converts the first element of a string into upper case character if it is a lower-case character, it ignores remaining characters.
• If the first character is an upper-case character, it returns same string.

Syntax: variable name. capitalize ()

Ex:

5. Title():

• It converts first letter of every word into a capital letter and remaining will be smaller letters.
• It returns new string.

Syntax: variable name. title ()

Ex:

6. Count():

• It is used to count how many times a character or a sequence of charcaters is occuring inside a string.
• It returns number not string.

Syntax: variable name. count (“substring”)

Syntax of count () with range:

→ variable name. count (“substring” , start index , end index )

Ex:

7.Index():

• It is used to find the first occurance of a substring not only for a single character (“a”), also for a sequence of characters (“abc”).
• If element or substring not present, index() returns value error.

Syntax: variable name. index (“substring”)

Syntax of index () with range:

→ variable name. index(“substring” , start index , end index )

Ex:

8. Find():

• It is used to find the first occurance of a substring not only for a single character (“a”), also for a sequence of characters (“abc”).
• Both index() and find() are same but only one difference, If element or substring not present, index() returns value error but find() returns -1.

Syntax: variable name. find(“substring”)

Syntax of find() with range:

→ variable name. find(“substring” , start index , end index )

Ex:

9.rindex():

• Same as index(), but i checks from right to left.
• In this start_index and end_index must be from left to right but output counts from right to left.

Syntax: variable name. rindex (“substring”)

Syntax of rindex () with range:

→ variable name. rindex(“substring” , start index , end index )

Ex:

10. rfind():

• Same as find(), but i checks from right to left.
• In this start_index and end_index must be from left to right but output counts from right to left.
• If start_index and end_index not from left to right it returns -1.

Syntax: variable name. rfind(“substring”)

Syntax of rfind() with range:

→ variable name. rfind(“substring” , start index , end index )

Ex:

11. Replace():

• It is used to replace a substring with an another string inside a string.

Syntax: variable name. replace(“substring” , “string”)

Syntax of replace() with maxium_limit:

→ variable name. replace(“substring” , “string” , max_limit)

Ex:

12. Strip():

• It is used to remove any substring from the starting and ending position.

Syntax: variable name. strip(“substring”)

Ex:

13. lstrip():

• It removes character from starting position.

Syntax: variable name. lstrip(“substring”)

Ex:

14. rstrip():

• It removes character from ending position.

Syntax: variable name. rstrip(“substring”)

Ex:

15. Split():

• It is used to divide or split the entire string into substring based on substring.
• Default substring is space( ).
• It will perform split from left to right and creates the group from left to right.
• If there is nothing left to split it returns empty string.
• Inside split not use empty seperator, Ex: var.split().

Syntax: variable name. split(“substring”)

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Syntax of split() with maximum number of splits:

→ variable name. split(“substring” , number(used to control number of splits))

Ex:

16. rsplit():

• It will perform split from right to left and creates the group from left to right.

Syntax: variable name. rsplit(“substring”)

Syntax of rsplit() with maximum number of splits:

→ variable name. rsplit(“substring” , number(used to control number of splits)))

Ex:

17.Partition():

• It is used to split or divide the entire string into three parts.
• If there is an empty string it returns three empty strings.

Syntax: variable name. partiton(“before value of split” , “actual value of split” , “after value of split”)

Ex:

18. Center():

• It is used to make the string appear approximately at the center of new string.

Syntax: variable name. center(length of new string)

Syntax: variable name. center(length of new string , “character which we want oresent at starting and ending of string”)

Ex:

19. Zfill():

• It fills starting element as zero (‘0’).
• It used in NLP.

Syntax: variable name. zfill(number (length of new string))

Ex:

20. Maketrans():

• It creates a mapping table.
• input — — — maps — — — output.
• Both input and output string length should be same.

Syntax: str.maketrans( string(input) , string(output))

Ex:

21. Translate():

• It shows or returns mapping table.

Syntax: var_name. translate(mapping table name)

Ex:

22. isupper():

• It checks whether all the alphabets inside the string is upper case or not.
• If all are upper case it returns True, otherwise False.

Syntax: var_name. isupper()

Ex:

23. islower():

• It checks whether all the alphabets inside the string is lower case or not.
• If all are lower case it returns True, otherwise False.

Syntax: var_name. islower()

Ex:

24. istitle():

• It checks whether every words first alphabet is upper case or not and remainig are lower case or not.
• If correct returns True, otherwise False.

Syntax: var_name. istitle()

Ex:

25. isdigit():

• It checks all the elements in a string are numbers or not.
• If correct returns True, otherwise False.

Syntax: var_name. isdigit()

Ex:

26. isalpha():

• It checks all the elements in a string are alphabets or not.
• If correct returns True, otherwise False.

Syntax: var_name. isalpha()

Ex:

27. isalnum():

• It checks all the elements in a string either alphabets or numbers or not.
• If correct returns True, otherwise False.

Syntax: var_name. isalnum()

Ex:

28. isspace():

• It checks all the elements in a string are spaces or not.
• If correct returns True, otherwise False.

Syntax: var_name. isspace()

Ex:

29. isidentifier():

• It checks whether the string is valid identifier or not by using naming convention means string starts with (a-z) or (0–9) or (_).
• If correct returns True, otherwise False.

Syntax: var_name. isidentifier()

Ex:

30. Startswith():

• It checks whether the string starts with the given substring or not.
• If correct returns True, otherwise False.

Syntax: var_name. startswith(“substring”)

Ex:

31. Endswith():

• It checks whether the string ends with the given substring or not.
• If correct returns True, otherwise False.

Syntax: var_name. endswith(“substring”)

Ex:

32. Format():

• It is used to combine a string data with other data type which gives a new string data.

Syntax: var_name. format(value1,value2,…,value n)

Ex: