I need to create a summary table at the end of a log with some values that
are obtained inside a class. The table needs to be printed in fixed-width
format. I have the code to do this already, but I need to limit Strings,
doubles and ints to a fixed-width size that is hard-coded in the code.
So, suppose I want to print a fixed-width table with
int,string,double,string
int,string,double,string
int,string,double,string
int,string,double,string
and the fixed widths are: 4, 5, 6, 6.
If a value exceeds this width, the last characters need to be cut off. So
for example:
124891, difference, 22.348, montreal
the strings that need to be printed ought to be:
1248 diffe 22.348 montre
I am thinking I need to do something in the constructor that forces a
string not to exceed a certain number of characters. I will probably
cast the doubles and ints to a string, so I can enforce the maximum width
requirements.
I don't know which method does this or if a string can be instantiated to
behave taht way. Using the formatter only helps with the
fixed-with formatting for printing the string, but it does not actually
chop characters that exceed the maximum length.
You can also use String.format("%3.3s", "abcdefgh"). The first digit is the minimum length (the string will be left padded if it's shorter), the second digit is the maxiumum length and the string will be truncated if it's longer. So
System.out.printf("'%3.3s' '%3.3s'", "abcdefgh", "a");
will produce
'abc' ' a'
(you can remove quotes, obviously).
Use this to cut off the non needed characters:
String.substring(0, maxLength);
Example:
String aString ="123456789";
String cutString = aString.substring(0, 4);
// Output is: "1234"
To ensure you are not getting an IndexOutOfBoundsException when the input string is less than the expected length do the following instead:
int maxLength = (inputString.length() < MAX_CHAR)?inputString.length():MAX_CHAR;
inputString = inputString.substring(0, maxLength);
If you want your integers and doubles to have a certain length then I suggest you use NumberFormat to format your numbers instead of cutting off their string representation.
For readability, I prefer this:
if (inputString.length() > maxLength) {
inputString = inputString.substring(0, maxLength);
}
over the accepted answer.
int maxLength = (inputString.length() < MAX_CHAR)?inputString.length():MAX_CHAR;
inputString = inputString.substring(0, maxLength);
You can use the Apache Commons StringUtils.substring(String str, int start, int end) static method, which is also null safe.
See: http://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/StringUtils.html#substring%28java.lang.String,%20int,%20int%29
and http://commons.apache.org/proper/commons-lang/javadocs/api-2.6/src-html/org/apache/commons/lang/StringUtils.html#line.1961
You can achieve this easily using
shortString = longString.substring(0, Math.min(s.length(), MAX_LENGTH));
If you just want a maximum length, use StringUtils.left! No if or ternary ?: needed.
int maxLength = 5;
StringUtils.left(string, maxLength);
Output:
null -> null
"" -> ""
"a" -> "a"
"abcd1234" -> "abcd1"
Left Documentation
The solution may be java.lang.String.format("%" + maxlength + "s", string).trim(), like this:
int maxlength = 20;
String longString = "Any string you want which length is greather than 'maxlength'";
String shortString = "Anything short";
String resultForLong = java.lang.String.format("%" + maxlength + "s", longString).trim();
String resultForShort = java.lang.String.format("%" + maxlength + "s", shortString).trim();
System.out.println(resultForLong);
System.out.println(resultForShort);
ouput:
Any string you want w
Anything short
Ideally you should try not to modify the internal data representation for the purpose of creating the table. Whats the problem with String.format()? It will return you new string with required width.
I have a number as
Double d = 100.000000;
I want to remove the decimal point and print the values as 100000000
(Note I am using java)
It is impossible. double doesn't store zeroes after decimal point so 1.0000 is equal to 1.0.
Hint: you can use BigDecimal for this. It have scale.
I'm afraid 100.000000 does not equal 100000000 and as mentioned by #talex, double doesn't store the zeros after the decimal point.
Your best bet is to use a String and remove the . manually:
String s = "100.000000";
System.out.println(s.replaceAll("\\.", "")); //note '.' needs to be escaped
Output:
100000000
You could parse it as a Double then if necessary.
Format the value using String.format and the remove the separator.
double d = 100.000;
String formatted = String.format(
Locale.US, //Using a Locale US to be sure the decimal separator is a "."
"%5f", //A decimal value with 5decimal
d) //The value to format
.replace(".", ""); //remove the separator
System.out.println(formatted);
100000000
Other examples :
100.000123456 > 100000123
You can see that the value is truncated, it is important to understand that.
Note that I have set the String to have 5 decimal number, but this up to you.
the double does not store the number as 100.0000 it just stored as 100.0 that means any unnecessary zeros on the right will be deleted but if the number was like this 100.01234 u can use this trick
Double d = 100.01245;
String text = Double.toString(d);
text.replace(".","");
d = Double.parseDouble(text);
or u can store the number as sting from the beginning
String text = "100.000000";
d.replace(".","");
double d = Double.parseDouble(text);
Hello Im new to programming
and as title I was wonder how you can find last digit of any given number?
for example when entering in 5.51123123 it will display 3
All I know is I should use charAt
Should I use while loop?
thanks in advance
You would want to do something like this:
double number = 5.51123123;
String numString = number + "";
System.out.println(numString.charAt(numString.length()-1));
When you do the number + "", Java "coerces" the type of number from a double to a string and allows you to perform string functions on it.
The numString.length()-1 is because numString.length() returns the count of all the characters in the string BUT charAt() indexes into the string and its indexing begins at 0, so you need to do the -1 or you'll get a StringIndexOutOfBoundsException.
You can use below function simply and you can customize data types accordingly,
private int getLastDigit(double val){
String tmp = String.valueOf(val);
return Integer.parseInt(tmp.substring(tmp.length()-1));
}
You can't use charAt on a floating point variable (or any other data type other than Strings). (Unless you define a charAt method for your own classes...)
You can, however, convert that floating point number to a string and check the charAt(str.length()-1).
Convert your float variable to string and use charAt(strVar.length - 1).
double a=5.51123123;
String strVar=String.valueOf(a);
System.out.print(strVar.charAt(strVar.length -1);
Double doubleNo = 5.51123123;
String stringNo = doubleNo.toString();
System.out.println(stringNo.charAt(stringNo.length()-1));
I'm using Selenium WebDriver (Java) and passing the String value that has decimal point and leading zero. I want to remove it. This is what I'm trying but doesn't work:
String data=2000.0
Long.parseLong(data);
(long)Double.parseDouble("2000.0");
It first converts the String to double and then converts it to long.
You can do this:
String data = "2000.0";
int i = (int)Double.parseDouble(data);
You can also implement this -
String data = "2000.0";
int i = Integer.parseInt(data);
I have following string in my java class
String str="0000000000008";
Now I want to increment that so that the next value should be 0000000000009
For that purpose, I tried to cast this String str into Integer
Integer i=Integer.parseFloat(str)+1;
and when I print the value of i it prints only 17(as it removes the leading 0's from string at the time of cast).
How can I increment the String value, so that the leading 0's will remain, and the series will continue?
Practical solution - use String.format:
str = String.format("%013d", Long.parseLong(str)+1);
You are on the correct path. First parse to Long:
long cur = Long.parseLong("0000000000008");
increment and format back to String with leading 0s:
new java.text.DecimalFormat("0000000000000").format(cur + 1);
or alternatively:
String.format("%013d", Long.valueOf(cur));