A program for formatting tables copied from excel into the LaTeX tabular environment.

generate_table.go

package main

import (
	"os"
	"fmt"
	"math"
	"strconv"
	"strings"
	"errhandler"
	"text/template"
)

// Raw data copied from excel is tab delimited
const raw = `F	Gain	Phase
1.0	-0.8	180.4
10.0	-0.8	180.1
100.0	-0.8	178.9
1000.0	0.0	166.6
10000.0	-21.7	-19.1
100000.0	-47.1	-131.5
1000000.0	-47.6	-105.7
2000.0	2.8	143.8
3000.0	5.0	86.6
4000.0	-0.6	32.5
3870.0	0.0	36.9
2950.0	5.0	90.4
4360.0	-3.0	23.2`

type Table struct {
	Headers string
	Rows []string
	Caption string
	ColumnCount int
}

// Returns the alignment parameter based on the number of columns: |c|c| ...
func (t Table) Alignment() string {
	return strings.Repeat("|c", t.ColumnCount) + "|"
}

// Returns a list of lines
func SplitLines(i string) []string {
	return strings.Split(i, "\n")
}

func ParseTable(i, caption string) Table {
	var table Table
	
	// Split into lines
	lines := SplitLines(raw)
	
	// Parse the headers and store the caption
	table.ParseHeader(lines[0])
	table.Caption = caption
	
	// Parse each row
	for _, line := range lines[1:] {
		table.ParseRow(line)
	}
	
	return table
}

func (t *Table) ParseHeader(i string) {
	result := make([]string, 0)
	// Split on tabs and wrap each word in $'s
	// Most of the time, first letter is capitalized,
	// rest of the word is subscripted
	for _, j := range strings.Split(i, "\t") {
		if len(j) == 1 {
			result = append(result, fmt.Sprintf("$%s$", j))
		} else {
			result = append(result, fmt.Sprintf("$%c_{%s}$", j[0], j[1:]))
		}
	}
	// Set the column count for printing the alignment parameter later
	t.ColumnCount = len(result)
	// Join the headers with the cell separation character &
	t.Headers = strings.Join(result, " & ")
}

func (t *Table) ParseRow(i string) {
	result := make([]string, 0)
	// Split on tabs
	for _, j := range strings.Split(i, "\t") {
		// Parse the number
		temp, err := strconv.ParseFloat(j, 64)
		// So long as we didn't encounter an error add it to the list
		if err == nil {
			// Render the number in engineering notation
			result = append(result, EngineeringNotation(float64(temp)))
		}
	}
	// Join all rows with the cell separation character &
	t.Rows = append(t.Rows, strings.Join(result, " & "))
}

func EngineeringNotation(i float64) string {
	// List of magnitudes for siunitx
	order := map[int]string{
		-24: "\\yocto", -21: "\\zepto", -18: "\\atto", -15: "\\femto",
		-12: "\\pico", -9: "\\nano", -6: "\\micro", -3: "\\milli", 0: "",
		3: "\\kilo", 6: "\\mega", 9: "\\giga", 12: "\\tera", 15: "\\peta",
		18: "\\exa", 21: "\\zetta", 24: "\\yotta"}
	
	// Round to the nearest integer magnitude
	magnitude := int(math.Floor(math.Log10(math.Abs(i)) + 0.5))
	// Round to nearest multiple of 3
	quantized := (magnitude / 3) * 3
	
	// Would normally generate NaN when rendering to text
	if i == 0.0 {
		return fmt.Sprintf("$%0.1f\\si{}$", i)
	}
	
	return fmt.Sprintf("$%0.1f\\si{%s}$", i * math.Pow10(-quantized), order[quantized])
}

func main() {
	// Parse the table with the given caption
	table := ParseTable(raw, "Measured gain and phase at various points in the frequency domain.")
	
	// Set the delimiters before parsing, using {{ and }} is
	// difficult with LaTeX since it uses { and } in so many places
	t := template.New("table.txt").Delims("<<", ">>")
	
	// Parse the table, exit if we couldn't
	_, err := t.ParseFiles("table.txt")
	errhandler.Handle("Error parsing template: ", err)
	
	// Execute the template with the parsed table
	// exit if an error occurs
	err = t.Execute(os.Stdout, table)
	errhandler.Handle("Error executing template: ", err)
}

output.tex

\begin{table}[p]
	\begin{minipage}[b]{0.5\linewidth}
		\centering
		\begin{tabular}{|c|c|c|}
			\hline
			$F$ & $G_{ain}$ & $P_{hase}$ \\
			\hline
			$1.0\si{}$ & $-0.8\si{}$ & $180.4\si{}$ \\
			\hline
			$10.0\si{}$ & $-0.8\si{}$ & $180.1\si{}$ \\
			\hline
			$100.0\si{}$ & $-0.8\si{}$ & $178.9\si{}$ \\
			\hline
			$1.0\si{\kilo}$ & $0.0\si{}$ & $166.6\si{}$ \\
			\hline
			$10.0\si{\kilo}$ & $-21.7\si{}$ & $-19.1\si{}$ \\
			\hline
			$100.0\si{\kilo}$ & $-47.1\si{}$ & $-131.5\si{}$ \\
			\hline
			$1.0\si{\mega}$ & $-47.6\si{}$ & $-105.7\si{}$ \\
			\hline
			$2.0\si{\kilo}$ & $2.8\si{}$ & $143.8\si{}$ \\
			\hline
			$3.0\si{\kilo}$ & $5.0\si{}$ & $86.6\si{}$ \\
			\hline
			$4.0\si{\kilo}$ & $-0.6\si{}$ & $32.5\si{}$ \\
			\hline
			$3.9\si{\kilo}$ & $0.0\si{}$ & $36.9\si{}$ \\
			\hline
			$3.0\si{\kilo}$ & $5.0\si{}$ & $90.4\si{}$ \\
			\hline
			$4.4\si{\kilo}$ & $-3.0\si{}$ & $23.2\si{}$ \\
			\hline
		\end{tabular}
		\caption{Measured gain and phase at various points in the frequency domain.}
	\end{minipage}
\end{table}

table.txt

\begin{table}[p]
	\begin{minipage}[b]{0.5\linewidth}
		\centering
		\begin{tabular}{<<.Alignment>>}
			\hline
			<<.Headers>> \\
			\hline
		<<range .Rows>>	<<.>> \\
			\hline
		<<end>>\end{tabular}
		\caption{<<.Caption>>}
	\end{minipage}
\end{table}