# Remove uppercase, lowercase, special, numeric, and non-numeric characters from a String

• Difficulty Level : Medium
• Last Updated : 03 Jan, 2023

Given string str of length N, the task is to remove uppercase, lowercase, special, numeric, and non-numeric characters from this string and print the string after the simultaneous modifications.

Examples:

Input: str = “GFGgfg123\$%”

Output: After removing uppercase characters: gfg123\$%

After removing lowercase characters: GFG123\$%

After removing special characters: GFGgfg123

After removing numeric characters: GFGgfg\$%

After removing non-numeric characters: 123

Input: str = “J@va12”

Output: After removing uppercase characters: @va12

After removing lowercase characters: J@12

After removing special characters: Jva12

After removing numeric characters: J@va

After removing non-numeric characters: 12

Naive Approach: The simplest approach is to iterate over the string and remove uppercase, lowercase, special, numeric, and non-numeric characters. Below are the steps:

1. Traverse the string character by character from start to end.

2. Check the ASCII value of each character for the following conditions:

• If the ASCII value lies in the range of [65, 90], then it is an uppercase character. Therefore, skip such characters and add the rest characters in another string and print it.
• If the ASCII value lies in the range of [97, 122], then it is a lowercase character. Therefore, skip such characters and add the rest characters in another string and print it.
• If the ASCII value lies in the range of [32, 47], [58, 64], [91, 96], or [123, 126] then it is a special character. Therefore, skip such characters and add the rest characters in another string and print it.
• If the ASCII value lies in the range of [48, 57], then it is a numeric character. Therefore, skip such characters and add the rest characters in another string and print it.
• Else the character is a non-numeric character. Therefore, skip such characters and add the rest characters in another string and print it.

Time Complexity: O(N)
Auxiliary Space: O(1)

Regular Expression Approach: The idea is to use regular expressions to solve this problem. Below are the steps:

1. Create regular expressions to remove uppercase, lowercase, special, numeric, and non-numeric characters from the string as mentioned below:

• regexToRemoveUpperCaseCharacters  = “[A-Z]”
• regexToRemoveLowerCaseCharacters = “[a-z]”
• regexToRemoveSpecialCharacters = “[^A-Za-z0-9]”
• regexToRemoveNumericCharacters = “[0-9]”
• regexToRemoveNon-NumericCharacters = “[^0-9]”

2. Compile the given regular expressions to create the pattern using Pattern.compile() method.

3. Match the given string with all the above Regular Expressions using Pattern.matcher().

4. Replace every matched pattern with the target string using the Matcher.replaceAll() method.

Below is the implementation of the above approach:

## C++

 `// C++ program to remove uppercase, lowercase``// special, numeric, and non-numeric characters``#include ``#include ``using` `namespace` `std;` `// Function to remove uppercase characters``string removingUpperCaseCharacters(string str)``{``  ``// Create a regular expression``  ``const` `regex pattern(``"[A-Z]"``);` `  ``// Replace every matched pattern with the``  ``// target string using regex_replace() method``  ``return` `regex_replace(str, pattern, ``""``);``}` `// Function to remove lowercase characters``string removingLowerCaseCharacters(string str)``{``  ``// Create a regular expression``  ``const` `regex pattern(``"[a-z]"``);` `  ``// Replace every matched pattern with the``  ``// target string using regex_replace() method``  ``return` `regex_replace(str, pattern, ``""``);``}` `// Function to remove special characters``string removingSpecialCharacters(string str)``{``  ``// Create a regular expression``  ``const` `regex pattern(``"[^A-Za-z0-9]"``);` `  ``// Replace every matched pattern with the``  ``// target string using regex_replace() method``  ``return` `regex_replace(str, pattern, ``""``);``}` `// Function to remove numeric characters``string removingNumericCharacters(string str)``{``  ``// Create a regular expression``  ``const` `regex pattern(``"[0-9]"``);` `  ``// Replace every matched pattern with the``  ``// target string using regex_replace() method``  ``return` `regex_replace(str, pattern, ``""``);``}` `// Function to remove non-numeric characters``string removingNonNumericCharacters(string str)``{``  ``// Create a regular expression``  ``const` `regex pattern(``"[^0-9]"``);` `  ``// Replace every matched pattern with the``  ``// target string using regex_replace() method``  ``return` `regex_replace(str, pattern, ``""``);``}` `int` `main()``{``  ``// Given String str``  ``string str = ``"GFGgfg123\$%"``;` `  ``// Print the strings after the simultaneous``  ``// modifications``  ``cout << ``"After removing uppercase characters: "``       ``<< removingUpperCaseCharacters(str) << endl;``  ``cout << ``"After removing lowercase characters: "``       ``<< removingLowerCaseCharacters(str) << endl;``  ``cout << ``"After removing special characters: "``       ``<< removingSpecialCharacters(str) << endl;``  ``cout << ``"After removing numeric characters: "``       ``<< removingNumericCharacters(str) << endl;``  ``cout << ``"After removing non-numeric characters: "``       ``<< removingNonNumericCharacters(str) << endl;` `  ``return` `0;``}` `// This article is contributed by yuvraj_chandra`

## Java

 `// Java program to remove uppercase, lowercase``// special, numeric, and non-numeric characters``import` `java.util.regex.Matcher;``import` `java.util.regex.Pattern;``public` `class` `GFG``{` `    ``// Function to remove uppercase characters``    ``public` `static` `String``    ``removingUpperCaseCharacters(String str)``    ``{` `        ``// Create a regular expression``        ``String regex = ``"[A-Z]"``;` `        ``// Compile the regex to create pattern``        ``// using compile() method``        ``Pattern pattern = Pattern.compile(regex);` `        ``// Get a matcher object from pattern``        ``Matcher matcher = pattern.matcher(str);` `        ``// Replace every matched pattern with the``        ``// target string using replaceAll() method``        ``return` `matcher.replaceAll(``""``);``    ``}` `    ``// Function to remove lowercase characters``    ``public` `static` `String``    ``removingLowerCaseCharacters(String str)``    ``{` `        ``// Create a regular expression``        ``String regex = ``"[a-z]"``;` `        ``// Compile the regex to create pattern``        ``// using compile() method``        ``Pattern pattern = Pattern.compile(regex);` `        ``// Get a matcher object from pattern``        ``Matcher matcher = pattern.matcher(str);` `        ``// Replace every matched pattern with the``        ``// target string using replaceAll() method``        ``return` `matcher.replaceAll(``""``);``    ``}` `    ``// Function to remove special characters``    ``public` `static` `String``    ``removingSpecialCharacters(String str)``    ``{` `        ``// Create a regular expression``        ``String regex = ``"[^A-Za-z0-9]"``;` `        ``// Compile the regex to create pattern``        ``// using compile() method``        ``Pattern pattern = Pattern.compile(regex);` `        ``// Get a matcher object from pattern``        ``Matcher matcher = pattern.matcher(str);` `        ``// Replace every matched pattern with the``        ``// target string using replaceAll() method``        ``return` `matcher.replaceAll(``""``);``    ``}` `    ``// Function to remove numeric characters``    ``public` `static` `String``    ``removingNumericCharacters(String str)``    ``{` `        ``// Create a regular expression``        ``String regex = ``"[0-9]"``;` `        ``// Compile the regex to create pattern``        ``// using compile() method``        ``Pattern pattern = Pattern.compile(regex);` `        ``// Get a matcher object from pattern``        ``Matcher matcher = pattern.matcher(str);` `        ``// Replace every matched pattern with the``        ``// target string using replaceAll() method``        ``return` `matcher.replaceAll(``""``);``    ``}` `    ``// Function to remove non-numeric characters``    ``public` `static` `String``    ``removingNonNumericCharacters(String str)``    ``{` `        ``// Create a regular expression``        ``String regex = ``"[^0-9]"``;` `        ``// Compile the regex to create pattern``        ``// using compile() method``        ``Pattern pattern = Pattern.compile(regex);` `        ``// Get a matcher object from pattern``        ``Matcher matcher = pattern.matcher(str);` `        ``// Replace every matched pattern with the``        ``// target string using replaceAll() method``        ``return` `matcher.replaceAll(``""``);``    ``}` `    ``// Driver Code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Given String str``        ``String str = ``"GFGgfg123\$%"``;` `        ``// Print the strings after the simultaneous``        ``// modifications``        ``System.out.println(``            ``"After removing uppercase characters: "``            ``+ removingUpperCaseCharacters(str));``        ``System.out.println(``            ``"After removing lowercase characters: "``            ``+ removingLowerCaseCharacters(str));``        ``System.out.println(``            ``"After removing special characters: "``            ``+ removingSpecialCharacters(str));``        ``System.out.println(``            ``"After removing numeric characters: "``            ``+ removingNumericCharacters(str));``        ``System.out.println(``            ``"After removing non-numeric characters: "``            ``+ removingNonNumericCharacters(str));``    ``}``}`

## Python3

 `# Python3 program to remove``# uppercase, lowercase special,``# numeric, and non-numeric characters``import` `re` `# Function to remove``# uppercase characters``def` `removingUpperCaseCharacters(``str``):` `    ``# Create a regular expression``    ``regex ``=` `"[A-Z]"` `    ``# Replace every matched pattern ``    ``# with the target string using``    ``# sub() method``    ``return` `(re.sub(regex, "", ``str``))` `# Function to remove lowercase``# characters``def` `removingLowerCaseCharacters(``str``):` `    ``# Create a regular expression``    ``regex ``=` `"[a-z]"` `    ``# Replace every matched``    ``# pattern with the target``    ``# string using sub() method``    ``return` `(re.sub(regex, "", ``str``))` `def` `removingSpecialCharacters(``str``):` `    ``# Create a regular expression``    ``regex ``=` `"[^A-Za-z0-9]"` `    ``# Replace every matched pattern``    ``# with the target string using``    ``# sub() method``    ``return` `(re.sub(regex, "", ``str``))` `def` `removingNumericCharacters(``str``):` `    ``# Create a regular expression``    ``regex ``=` `"[0-9]"` `    ``# Replace every matched``    ``# pattern with the target``    ``# string using sub() method``    ``return` `(re.sub(regex, "", ``str``))` `def`  `removingNonNumericCharacters(``str``):` `    ``# Create a regular expression``    ``regex ``=` `"[^0-9]"` `    ``# Replace every matched pattern``    ``# with the target string using``    ``# sub() method``    ``return` `(re.sub(regex, "", ``str``))` `str` `=` `"GFGgfg123\$%"``print``(``"After removing uppercase characters:"``,``       ``removingUpperCaseCharacters(``str``))``print``(``"After removing lowercase characters:"``,``       ``removingLowerCaseCharacters(``str``))``print``(``"After removing special characters:"``,``       ``removingSpecialCharacters(``str``))``print``(``"After removing numeric characters:"``,``       ``removingNumericCharacters(``str``))``print``(``"After removing non-numeric characters:"``,``       ``removingNonNumericCharacters(``str``))` `# This code is contributed by avanitrachhadiya2155`

## C#

 `// C# program to remove uppercase, lowercase``// special, numeric, and non-numeric characters``using` `System;``using` `System.Text.RegularExpressions;``public` `class` `GFG``{` `  ``// Function to remove uppercase characters``  ``public` `static` `string``    ``removingUpperCaseCharacters(``string` `str)``  ``{` `    ``// Create a regular expression``    ``string` `regex = ``"[A-Z]"``;` `    ``// Replace every matched pattern with the``    ``// target string using Replace method``    ``return` `Regex.Replace(str, regex, ``""``);``  ``}` `  ``// Function to remove lowercase characters``  ``public` `static` `string``    ``removingLowerCaseCharacters(``string` `str)``  ``{` `    ``// Create a regular expression``    ``string` `regex = ``"[a-z]"``;` `    ``// Replace every matched pattern with the``    ``// target string using Replace method``    ``return` `Regex.Replace(str, regex, ``""``);``  ``}` `  ``// Function to remove special characters``  ``public` `static` `string``    ``removingSpecialCharacters(``string` `str)``  ``{` `    ``// Create a regular expression``    ``string` `regex = ``"[^A-Za-z0-9]"``;` `    ``// Replace every matched pattern with the``    ``// target string using Replace method``    ``return` `Regex.Replace(str, regex, ``""``);``  ``}` `  ``// Function to remove numeric characters``  ``public` `static` `string``    ``removingNumericCharacters(``string` `str)``  ``{` `    ``// Create a regular expression``    ``string` `regex = ``"[0-9]"``;` `    ``// Replace every matched pattern with the``    ``// target string using Replace method``    ``return` `Regex.Replace(str, regex, ``""``);``  ``}` `  ``// Function to remove non-numeric characters``  ``public` `static` `string``    ``removingNonNumericCharacters(``string` `str)``  ``{` `    ``// Create a regular expression``    ``string` `regex = ``"[^0-9]"``;` `    ``// Replace every matched pattern with the``    ``// target string using Replace method``    ``return` `Regex.Replace(str, regex, ``""``);``  ``}` `  ``// Driver Code``  ``public` `static` `void` `Main()``  ``{``    ``// Given string str``    ``string` `str = ``"GFGgfg123\$%"``;` `    ``// Print the strings after the simultaneous``    ``// modifications``    ``Console.WriteLine(``      ``"After removing uppercase characters: "``      ``+ removingUpperCaseCharacters(str));``    ``Console.WriteLine(``      ``"After removing lowercase characters: "``      ``+ removingLowerCaseCharacters(str));``    ``Console.WriteLine(``      ``"After removing special characters: "``      ``+ removingSpecialCharacters(str));``    ``Console.WriteLine(``      ``"After removing numeric characters: "``      ``+ removingNumericCharacters(str));``    ``Console.WriteLine(``      ``"After removing non-numeric characters: "``      ``+ removingNonNumericCharacters(str));``  ``}``}` `// This code is contributed by Aman Kumar.`

## Javascript

 `// Javascript program to remove uppercase, lowercase``// special, numeric, and non-numeric characters` `// Function to remove uppercase characters``function` `removingUpperCaseCharacters(str)``{` `// Create a regular expression``let pattern = ``new` `RegExp(``"[A-Z]"``,``'g'``);` `// Replace every matched pattern with the``// target string using str.replace() method``return` `str.replace(pattern, ``""``);``}` `// Function to remove lowercase characters``function` `removingLowerCaseCharacters(str)``{` `// Create a regular expression``let pattern = ``new` `RegExp(``"[a-z]"``,``'g'``);` `// Replace every matched pattern with the``// target string using str.replace() method``return` `str.replace(pattern, ``""``);``}` `// Function to remove special characters``function` `removingSpecialCharacters(str)``{` `// Create a regular expression``let pattern = ``new` `RegExp(``"[^A-Za-z0-9]"``,``'g'``);` `// Replace every matched pattern with the``// target string using str.replace() method``return` `str.replace(pattern, ``""``);``}` `// Function to remove numeric characters``function` `removingNumericCharacters(str)``{` `// Create a regular expression``let pattern = ``new` `RegExp(``"[0-9]"``,``'g'``);` `// Replace every matched pattern with the``// target string using str.replace() method``return` `str.replace(pattern, ``""``);``}` `// Function to remove non-numeric characters``function` `removingNonNumericCharacters(str)``{` `// Create a regular expression``let pattern = ``new` `RegExp(``"[^0-9]"``,``'g'``);` `// Replace every matched pattern with the``// target string using str.replace() method``return` `str.replace(pattern, ``""``);``}` `// Given String str``let str = ``"GFGgfg123\$%"``;` `// Print the strings after the simultaneous``// modifications``console.log(``"After removing uppercase characters: "``    ``+ removingUpperCaseCharacters(str)+``"
"` `);``console.log(``"After removing lowercase characters: "``    ``+ removingLowerCaseCharacters(str)+``"
"` `);``console.log(``"After removing special characters: "``    ``+ removingSpecialCharacters(str)+``"
"` `);``console.log(``"After removing numeric characters: "``    ``+ removingNumericCharacters(str)+``"
"` `);``console.log(``"After removing non-numeric characters: "``+ removingNonNumericCharacters(str)+``"
"` `);``  ` `// This article is contributed by Pushpesh Raj`

Output

```After removing uppercase characters: gfg123\$%
After removing lowercase characters: GFG123\$%
After removing special characters: GFGgfg123
After removing numeric characters: GFGgfg\$%
After removing non-numeric characters: 123```

Time Complexity: O(N)

Auxiliary Space: O(1)

My Personal Notes arrow_drop_up