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| -rw-r--r-- | doc/textutils.texi | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/doc/textutils.texi b/doc/textutils.texi index 4f2a291a5..cbe6d7bb7 100644 --- a/doc/textutils.texi +++ b/doc/textutils.texi @@ -1796,6 +1796,22 @@ Sort numerically: the number begins each line; specifically, it consists of optional whitespace, an optional @samp{-} sign, and zero or more digits, optionally followed by a decimal point and zero or more digits. +@code{sort -n} uses what might be considered an unconventional method +to compare strings representing floating point numbers. Rather than +first converting each string to the C @code{double} type and then +comparing those values, sort aligns the decimal points in the two +strings and compares the strings a character at a time. One benefit +of using this approach is its speed. In practice this is much more +efficient than performing the two corresponding string-to-double (or even +string-to-integer) conversions and then comparing doubles. In addition, +there is no corresponding loss of precision. Converting each string to +@code{double} before comparison would limit precision to about 16 digits +on most systems. + +Note that neither a leading @samp{+} nor exponential notation is +recognized. To compare such strings numerically, use the @samp{-g} +option. + @item -r @opindex -r @cindex reverse sorting |