How to Convert a String value to Float value in Java with Examples

29 Jan, 2020
Given a String “str” in Java, the task is to convert this string to float type.
Examples:
Input: str = "1.0"
Output: 1.0

Input: str = "3.14"
Output: 3.14

Approach 1: (Naive Method)One method is to traverse the string and add the numbers one by one to the float type. This method is not an efficient approach.
Approach 2: (Using Float.parseFloat() method)The simplest way to do so is using parseFloat() method of Float class in java.lang package. This method takes the string to be parsed and returns the float type from it. If not convertible, this method throws error.
Syntax:
Float.parseFloat(str);

Below is the implementation of the above approach:
Example 1: To show successful conversion
// Java Program to convert string to float  class GFG {      // Function to convert String to Float    public static float convertStringToFloat(String str)    {          // Convert string to float        // using parseFloat() method        return Float.parseFloat(str);    }      // Driver code    public static void main(String[] args)    {          // The string value        String stringValue = "1.0";          // The expected float value        float floatValue;          // Convert string to float        floatValue = convertStringToFloat(stringValue);          // Print the expected float value        System.out.println(            stringValue            + " after converting into float = "            + floatValue);    }}
1.0 after converting into float = 1.0

Example 2: To show unsuccessful conversion
// Java Program to convert string to float  class GFG {      // Function to convert String to Float    public static void convertStringToFloat(String str)    {          float floatValue;          try {            // Convert string to float            // using parseFloat() method            floatValue = Float.parseFloat(str);              // Print the expected float value            System.out.println(                str                + " after converting into float = "                + floatValue);        }        catch (Exception e) {            // Print the error            System.out.println(                str                + " cannot be converted to float: "                + e.getMessage());        }    }      // Driver code    public static void main(String[] args)    {          // The string value        String str1 = "";        String str2 = null;        String str3 = "GFG";          // Convert string to float        // using parseFloat() method        convertStringToFloat(str1);        convertStringToFloat(str2);        convertStringToFloat(str3);    }}
cannot be converted to float: empty String
null cannot be converted to float: null
GFG cannot be converted to float: For input string: "GFG"

Approach 3: (Using Float.valueOf() method)The valueOf() method of Float class converts data from its internal form into human-readable form.
Syntax:
Float.valueOf(str);

Below is the implementation of the above approach:
Example 1: To show successful conversion
// Java Program to convert string to float  class GFG {      // Function to convert String to Float    public static float convertStringToFloat(String str)    {          // Convert string to float        // using valueOf() method        return Float.valueOf(str);    }      // Driver code    public static void main(String[] args)    {          // The string value        String stringValue = "1.0";          // The expected float value        float floatValue;          // Convert string to float        floatValue = convertStringToFloat(stringValue);          // Print the expected float value        System.out.println(            stringValue            + " after converting into float = "            + floatValue);    }}
1.0 after converting into float = 1.0

Java-Data Types
Java-Float
Java-String-Programs
Java
Java Programs
Java
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