Cannot cast from String to float in java

Question

long l = ((File)localObject).length();
  if (l >= 1024L)
  {
    if (l >= 1048576L)
    {
      if (l >= 1073741824L)
        str = Float.toString(Math.round(100.0F * ((float)l / 1.073742E+09F)) / 100.0F) + " GB";
      else
        str = Float.toString(Math.round(100.0F * ((float)str / 1048576.0F)) / 100.0F) + " MB";
    }
    else
      str = Float.toString(Math.round(100.0F * ((float)str / 1024.0F)) / 100.0F) + " KB";
  }
  else
    str = Long.toString(str) + " B";

else str = Long.toOctalString(str) + " B"; } return (String)str; }

Another error in 16 th Here i got the error in 9 th line and 12 th line Cannot cast from String to float in java

What causes you to think a float cast of a string should work? What if the string has an illegal format ("ABCNOTA NUMBER")? How can a cast work with bad data? Have you seen documentation or a tutorial that makes it look like this should work? — S.Lott
– S.Lott, Commented Feb 17, 2012 at 12:12
There's an error on the last line: maybe you should write str = Long.toString(l) + " B" — enzom83
– enzom83, Commented Feb 17, 2012 at 12:17
Also, please read the book "Clean code" by R.C. Martin. Your code is horrible to read with nested if-else-statements, magic numbers, nested arguments. What if a team member is to understand this code? That is impossible. I even think that in a week or two you won't be able to understand it yourself. — nhaarman
– nhaarman, Commented Feb 17, 2012 at 12:21

assylias · Accepted Answer · 2012-02-17 12:40:37Z

7

I suppose str is a String, in which case you need to use Float.valueOf(str) instead of (float)str.

Or more likely you meant (float)l instead of (float)str.

And as mentioned by enzom83, your last line should probably be:

str = Long.toString(l) + " B";

edited Feb 17, 2012 at 12:40

answered Feb 17, 2012 at 12:10

assylias

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1 Comment

user1129139 Over a year ago

here i got the error in line str = Long.toString(str) + " B"; The method toString(long) in the type Long is not applicable for the arguments (String)

shift66 · Accepted Answer · 2012-02-17 12:11:16Z

3

use parseFloat method Float.parseFloat(str)

answered Feb 17, 2012 at 12:11

shift66

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Comments

pablomolnar · Accepted Answer · 2012-02-17 12:29:42Z

2

Looks like you are trying to cast the String str to a float. Probably you have a mistake and you are supposed to use the l variable instead.

edited Feb 17, 2012 at 12:29

answered Feb 17, 2012 at 12:14

pablomolnar

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Comments

WarrenFaith · Accepted Answer · 2012-02-17 12:11:15Z

2

You can't use (float)str when str is a String.

Replace it with this (and catch possible exceptions!): Float.valueOf(str)

answered Feb 17, 2012 at 12:11

WarrenFaith

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Comments

nkm · Accepted Answer · 2012-02-18 06:20:40Z

1

Hm, sorry for my English

If str is a String that you can't convert into a float like this (float)str, you must use a Float method called parseFloat(String s), which returns a new float initialized to the value represented by the specified String

edited Feb 18, 2012 at 6:20

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answered Feb 17, 2012 at 12:23

budgie

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