Online Programming Reference Guides - Perl
[an error occurred while processing this directive]
Contents
[ < ] [ > ]   [ << ] [ Up ] [ >> ]         [Top] [Contents] [Index] [ ? ]
[an error occurred while processing this directive]

9.3 Field Widths with printf

Another useful feature of printf conversion (the % directives) lies in the area of field widths. These are values included in the % conversion directive to specify the width of a field and are especially useful in lining up columns of data. The field width value is placed between the % and the conversion character such as:

printf "%7d\n", 12345;
printf "%7d\n", 123;
will create right justified output:

12345
  123
Negative values can be used to create left justified fixed width data fields. This is of particular use when creating multi-column data output:

printf "%-10d", 12345;
printf "%-10d\n", 123;
printf "%-10d", 1;
printf "%-10d\n", 123456;
This will output the data in left justified columns:

12345     123
1         123456
The conversion value can also be used to control the number of decimal places displayed for floating point (%f) numbers:

printf "%15.3f\n", 53/9;
printf "%15.4f\n", 53/9;
printf "%15.7f\n", 53/9;
This will output right justified data with varying numbers of digits after the decimal point as defined in the conversions:

    5.889
   5.8889
5.8888889



[an error occurred while processing this directive]