Number formatting

<!--- PLEASE DO NOT EDIT DIRECTLY. EDIT THE .md.in FILE PLEASE. ---> <div> <span class="quicklinks"> Quick links: &nbsp; <a class="quicklink" href="../reference-main-flag-list/index.html">Flags</a> &nbsp; <a class="quicklink" href="../reference-verbs/index.html">Verbs</a> &nbsp; <a class="quicklink" href="../reference-dsl-builtin-functions/index.html">Functions</a> &nbsp; <a class="quicklink" href="../glossary/index.html">Glossary</a> &nbsp; <a class="quicklink" href="../release-docs/index.html">Release docs</a> </span> </div> # Number formatting

The --ofmt flag

The command-line option --ofmt {format string} is the global number format for all numeric fields. Examples:

<pre class="pre-non-highlight-non-pair"> --ofmt %.9e --ofmt %.6f --ofmt %.0f </pre>

These are just familiar printf formats -- as of Miller 6.0.0, supported options are those at https://pkg.go.dev/fmt. Additionally, if you use leading width (e.g. %18.12f) then the output will contain embedded whitespace, which may not be what you want if you pipe the output to something else, particularly CSV. I use Miller's pretty-print format (mlr --opprint) to column-align numerical data.

<pre class="pre-highlight-in-pair"> <b>echo 'x=3.1,y=4.3' | mlr --ofmt '%8.3f' cat</b> </pre> <pre class="pre-non-highlight-in-pair"> x= 3.100,y= 4.300 </pre> <pre class="pre-highlight-in-pair"> <b>echo 'x=3.1,y=4.3' | mlr --ofmt '%11.8e' cat</b> </pre> <pre class="pre-non-highlight-in-pair"> x=3.10000000e+00,y=4.30000000e+00 </pre>

The format-values verb

To separately specify formatting for string, int, and float fields, you can use the format-values verb -- see that section for examples.

The fmtnum and hexfmt functions

To apply formatting to a single field, you can also use fmtnum function within mlr put. For example:

<pre class="pre-highlight-in-pair"> <b>echo 'x=3.1,y=4.3' | mlr put '$z=fmtnum($x*$y,"%08f")'</b> </pre> <pre class="pre-non-highlight-in-pair"> x=3.1,y=4.3,z=13.330000 </pre> <pre class="pre-highlight-in-pair"> <b>echo 'x=0xffff,y=0xff' | mlr put '$z=fmtnum(int($x*$y),"%08x")'</b> </pre> <pre class="pre-non-highlight-in-pair"> x=0xffff,y=0xff,z=00feff01 </pre>

Input conversion from hexadecimal is done automatically on fields handled by mlr put and mlr filter as long as the field value begins with 0x. To apply output conversion to hexadecimal on a single column, you may use fmtnum, or the keystroke-saving hexfmt function. Example:

<pre class="pre-highlight-in-pair"> <b>echo 'x=0xffff,y=0xff' | mlr put '$z=$x*$y'</b> </pre> <pre class="pre-non-highlight-in-pair"> x=0xffff,y=0xff,z=16711425 </pre> <pre class="pre-highlight-in-pair"> <b>echo 'x=0xffff,y=0xff' | mlr put '$z=hexfmt($x*$y)'</b> </pre> <pre class="pre-non-highlight-in-pair"> x=0xffff,y=0xff,z=0xfeff01 </pre>