Convert string to decimal number with 2 decimal places in Java

Question

In Java  I am trying to parse a string of format          to a float   The string should always have 2 decimal places   Even if the String has value 123 00  the float should also be 123 00  not 123 0   This is what I have so far   System out println  string liters of petrol putting in preferences is     stringLitersOfPetrol    Float litersOfPetrol   Float parseFloat stringLitersOfPetrol    DecimalFormat df   new DecimalFormat  0 00    df setMaximumFractionDigits 2    litersOfPetrol   Float parseFloat df format litersOfPetrol     System out println  liters of petrol before putting in editor      litersOfPetrol     It prints   string liters of petrol putting in preferences is 010 00  liters of petrol before putting in editor  10 0

User · Answer

Java convert a String to decimal    String dennis    0 00000008880000   double f   Double parseDouble dennis   System out println f   System out println String format    7f   f    System out println String format    9f   new BigDecimal f     System out println String format    35f   new BigDecimal f     System out println String format    2f   new BigDecimal f       This prints   8 88E-8 0 0000001 0 000000089 0 00000008880000000000000106383001366 0 00

User · Answer

This line is your problem   litersOfPetrol   Float parseFloat df format litersOfPetrol      There you formatted your float to string as you wanted  but but then that string got transformed again to a float  and then what you printed in stdout was  your float that got a standard formatting  Take a look at this code  import java text DecimalFormat   String stringLitersOfPetrol    123 00   System out println  string liters of petrol putting in preferences is   stringLitersOfPetrol   Float litersOfPetrol Float parseFloat stringLitersOfPetrol   DecimalFormat df   new DecimalFormat  0 00    df setMaximumFractionDigits 2   stringLitersOfPetrol   df format litersOfPetrol   System out println  liters of petrol before putting in editor     stringLitersOfPetrol     And by the way  when you want to use decimals  forget the existence of double and float as others suggested and just use BigDecimal object  it will save you a lot of headache

User · Answer

Float parseFloat   is the problem  as it returns a new float      Returns a new float initialized to the value represented by the specified String  as performed by the valueOf method of class Float    You are formatting just for the purpose of display   It doesn t mean the float will be represented by the same format internally     You can use java lang BigDecimal   I am not sure why are you using parseFloat   twice  If you want to display the float in a certain format then just format it and display it   Float litersOfPetrol Float parseFloat stringLitersOfPetrol   DecimalFormat df   new DecimalFormat  0 00    df setMaximumFractionDigits 2   System out println  liters of petrol before putting in editor  df format litersOfPetrol

User · Answer

Use BigDecimal   new BigDecimal theInputString     It retains all decimal digits  And you are sure of the exact representation since it uses decimal base  not binary base  to store the precision scale etc   And it is not subject to precision loss like float or double are  unless you explicitly ask it to

User · Answer

I just want to be sure that the float number will also have 2 decimal places after converting that string    You can t  because floating point numbers don t have decimal places  They have binary places  which aren t commensurate with decimal places   If you want decimal places  use a decimal radix

User · Answer

litersOfPetrol   Float parseFloat df format litersOfPetrol     System out println  liters of petrol before putting in editor     litersOfPetrol     You print Float here  that has no format at all   To print formatted float  just use  String formatted   df format litersOfPetrol   System out println  liters of petrol before putting in editor       formatted

[java] Convert string to decimal number with 2 decimal places in Java

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