f-Strings.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# f-Strings\n",
    "\n",
    "Desde Python 3.6 encontramos una nueva funcionalidad que simplificar el formateo gracias a la interpolación de cadenas. \n",
    "\n",
    "En lugar de poner esto:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hola Héctor\n"
     ]
    }
   ],
   "source": [
    "nombre = \"Héctor\"\n",
    "cadena = \"Hola {}\".format(nombre)\n",
    "print(cadena)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Podemos indicar que la cadena está formateada añadiendo `f\"\"` delante y pasando directamente las variables o datos interpretados:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hola Héctor\n"
     ]
    }
   ],
   "source": [
    "nombre = \"Héctor\"\n",
    "cadena = f\"Hola {nombre}\"\n",
    "print(cadena)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Como véis es muy útil y permite ahorrarnos algo de código."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Contenido interpretado"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "La suma de 10 y 5 es 15\n"
     ]
    }
   ],
   "source": [
    "a, b = 10, 5\n",
    "\n",
    "print(f\"La suma de {a} y {b} es {a+b}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "¡Hola Pepe!\n"
     ]
    }
   ],
   "source": [
    "def func():\n",
    "    return \"Pepe\"\n",
    "\n",
    "print(f\"¡Hola {func()}!\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "El número dos es 2\n"
     ]
    }
   ],
   "source": [
    "numero = {\"uno\":1, \"dos\": 2, \"tres\": 3}\n",
    "\n",
    "print(f\"El número dos es {numero['dos']}\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Formateos avanzados"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Alineamientos"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hola mundo                              \n"
     ]
    }
   ],
   "source": [
    "print(f\"{'Hola mundo':40}\")  # a la izquierda 40 caracteres"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hola mundo                              \n",
      "                              Hola mundo\n",
      "               Hola mundo               \n"
     ]
    }
   ],
   "source": [
    "texto = \"Hola mundo\"\n",
    "\n",
    "print(f\"{texto:40}\")    # a la izquierda 40 caracteres\n",
    "print(f\"{texto:>40}\")   # a la derecha 40 caracteres\n",
    "print(f\"{texto:^40}\")   # al centro 40 caracteres"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Truncamiento"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hola\n"
     ]
    }
   ],
   "source": [
    "print(f\"{texto:.4}\")   # primeros 4 caracteres"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Truncamiento con variables"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hola\n"
     ]
    }
   ],
   "source": [
    "limite = 4\n",
    "\n",
    "print(f\"{texto:.{limite}}\")   # primeros 4 caracteres"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Alineamiento con truncamiento"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "                          Hola\n",
      "Hola                          \n",
      "             Hola             \n"
     ]
    }
   ],
   "source": [
    "print(f\"{texto:>30.4}\")\n",
    "print(f\"{texto:<30.4}\")\n",
    "print(f\"{texto:^30.4}\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Alineamiento con truncamiento y variables"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "                          Hola\n",
      "Hola                          \n",
      "             Hola             \n"
     ]
    }
   ],
   "source": [
    "limite = 4\n",
    "longitud = 30\n",
    "\n",
    "print(f\"{texto:>{longitud}.{limite}}\")\n",
    "print(f\"{texto:<{longitud}.{limite}}\")\n",
    "print(f\"{texto:^{longitud}.{limite}}\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Formateo de números enteros, rellenados con espacios"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "     1\n",
      "    10\n",
      "   100\n",
      "  1000\n",
      " 10000\n",
      "100000\n"
     ]
    }
   ],
   "source": [
    "print(f\"{1:6d}\")\n",
    "print(f\"{10:6d}\")\n",
    "print(f\"{100:6d}\")\n",
    "print(f\"{1000:6d}\")\n",
    "print(f\"{10000:6d}\")\n",
    "print(f\"{100000:6d}\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Formateo de números enteros, rellenados con ceros"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "000001\n",
      "000010\n",
      "000100\n",
      "001000\n",
      "010000\n",
      "100000\n"
     ]
    }
   ],
   "source": [
    "print(f\"{1:06d}\")\n",
    "print(f\"{10:06d}\")\n",
    "print(f\"{100:06d}\")\n",
    "print(f\"{1000:06d}\")\n",
    "print(f\"{10000:06d}\")\n",
    "print(f\"{100000:06d}\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Formateo de números flotantes, rellenados con espacios"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "  3.142\n",
      "153.210\n"
     ]
    }
   ],
   "source": [
    "# 4 dígitos: 3 enteros, 1 punto y 3 decimales\n",
    "\n",
    "print(f\"{3.1415926:7.3f}\")   \n",
    "print(f\"{153.21:7.3f}\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Formateo de números flotantes, rellenados con ceros"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0003.1416\n",
      "0153.2100\n"
     ]
    }
   ],
   "source": [
    "# 9 dígitos: 4 enteros, 1 punto y 4 decimales\n",
    "\n",
    "print(f\"{3.1415926:09.4f}\")   \n",
    "print(f\"{153.21:09.4f}\")      "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Formateo de números con variables"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0000000003.1415926000\n"
     ]
    }
   ],
   "source": [
    "numero = 3.1415926\n",
    "longitud = 21       # 1 para el decimal\n",
    "decimales = 10\n",
    "\n",
    "print(f\"{numero:0{longitud}.{decimales}f}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3 (ipykernel)",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.10.5"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 1
}