Intente ejecutar este código eliminando uno por uno cada uno \pgfplotstablegetelem. Verás que los 2 subflotadores se irán moviendo paso a paso hacia el centro. ¿Por qué? Manteniéndolos todos el resultado es el siguiente. Necesito mantener la figura \newcommandde esta manera, pero al mismo tiempo centrada, ¿cómo puedo hacer?
\documentclass[a4paper,twoside,12pt]{book}
\usepackage[T1]{fontenc}
\usepackage[utf8x]{inputenc}
\usepackage[english]{babel}
\usepackage{tikz}
\usepackage{pgfplotstable, filecontents}
\usepackage{subfig}
\usepackage{float}
\newcommand{\iso}[1]{
\pgfplotstablegetelem{#1}{T}\of{coefficienti.dat}
\pgfmathsetmacro{\T}{\pgfplotsretval}
\pgfplotstablegetelem{#1}{K}\of{coefficienti.dat}
\pgfmathsetmacro{\K}{\pgfplotsretval}
\pgfplotstablegetelem{#1}{Q}\of{coefficienti.dat}
\pgfmathsetmacro{\Q}{\pgfplotsretval}
\pgfplotstablegetelem{#1}{Kf}\of{coefficienti.dat}
\pgfmathsetmacro{\Kf}{\pgfplotsretval}
\pgfplotstablegetelem{#1}{n}\of{coefficienti.dat}
\pgfmathsetmacro{\n}{\pgfplotsretval}
\pgfplotstablegetelem{#1}{Klf}\of{coefficienti.dat}
\pgfmathsetmacro{\Klf}{\pgfplotsretval}
\pgfplotstablegetelem{#1}{Qlf}\of{coefficienti.dat}
\pgfmathsetmacro{\Qlf}{\pgfplotsretval}
\pgfplotstablegetelem{#1}{m}\of{coefficienti.dat}
\pgfmathsetmacro{\m}{\pgfplotsretval}
\begin{tikzpicture}
\begin{axis}[
width=7cm,
domain=0:1,
xlabel=$Equilibrium$,
ylabel=$Sorbed$,
legend style={draw=none, at={(.9,.3)}}]
\end{axis}
\end{tikzpicture}
}
\begin{document}
\begin{filecontents*}{coefficienti.dat}
T K Q Kf n Klf Qlf m
400 0.0463 32.9 5.78 0.321 .0840 40.7 .675
500 0.154 23.8 6.33 0.281 .0722 86.8 .354
600 0.115 24.6 6.30 0.261 .0257 247 .280
700 1.68 24.2 12.1 0.153 .9760 32.0 .376
\end{filecontents*}
\begin{figure}[H]
\centering
\subfloat[]{\iso{0}}
\subfloat[]{\iso{0}}
\caption{This caption is centered, but not the 2 subfloats}
\end{figure}
\end{document}
Respuesta1
Tiene una buena oferta de espacios de final de línea. Poner %al final de líneas, a voluntad.
\documentclass[a4paper,twoside,12pt]{book}
\usepackage[T1]{fontenc}
\usepackage[utf8x]{inputenc}
\usepackage[english]{babel}
\usepackage{tikz}
\usepackage{pgfplotstable, filecontents}
\usepackage{subfig}
\usepackage{float}
\newcommand{\iso}[1]{%
\pgfplotstablegetelem{#1}{T}\of{coefficienti.dat}%
\pgfmathsetmacro{\T}{\pgfplotsretval}%
\pgfplotstablegetelem{#1}{K}\of{coefficienti.dat}%
\pgfmathsetmacro{\K}{\pgfplotsretval}%
\pgfplotstablegetelem{#1}{Q}\of{coefficienti.dat}%
\pgfmathsetmacro{\Q}{\pgfplotsretval}%
\pgfplotstablegetelem{#1}{Kf}\of{coefficienti.dat}%
\pgfmathsetmacro{\Kf}{\pgfplotsretval}%
\pgfplotstablegetelem{#1}{n}\of{coefficienti.dat}%
\pgfmathsetmacro{\n}{\pgfplotsretval}%
\pgfplotstablegetelem{#1}{Klf}\of{coefficienti.dat}%
\pgfmathsetmacro{\Klf}{\pgfplotsretval}%
\pgfplotstablegetelem{#1}{Qlf}\of{coefficienti.dat}%
\pgfmathsetmacro{\Qlf}{\pgfplotsretval}%
\pgfplotstablegetelem{#1}{m}\of{coefficienti.dat}%
\pgfmathsetmacro{\m}{\pgfplotsretval}%
\begin{tikzpicture}%
\begin{axis}[
width=7cm,
domain=0:1,
xlabel=$Equilibrium$,
ylabel=$Sorbed$,
legend style={draw=none, at={(.9,.3)}}]
\end{axis}%
\end{tikzpicture}%
}
\begin{document}
\begin{filecontents*}{coefficienti.dat}
T K Q Kf n Klf Qlf m
400 0.0463 32.9 5.78 0.321 .0840 40.7 .675
500 0.154 23.8 6.33 0.281 .0722 86.8 .354
600 0.115 24.6 6.30 0.261 .0257 247 .280
700 1.68 24.2 12.1 0.153 .9760 32.0 .376
\end{filecontents*}
\begin{figure}[H]
\centering
\subfloat[]{\iso{0}}
\subfloat[]{\iso{0}}
\caption{This caption is centered, but not the 2 subfloats}
\end{figure}
\end{document}
Tenga en cuenta que width=7cmes demasiado para encajar. Úselo width=0.5\linewidthen su lugar.
