{"id":1591,"date":"2018-11-23T20:54:15","date_gmt":"2018-11-23T19:54:15","guid":{"rendered":"https:\/\/pythonprogramming.altervista.org\/?p=1591"},"modified":"2018-11-26T08:51:51","modified_gmt":"2018-11-26T07:51:51","slug":"lets-make-graphs-with-matplotlib","status":"publish","type":"post","link":"https:\/\/pythonprogramming.altervista.org\/lets-make-graphs-with-matplotlib\/","title":{"rendered":"Let’s make graphs with MatPlotLib"},"content":{"rendered":"

Draw axis<\/h2>\n

To draw axis, you can do this:<\/p>\n

import matplotlib.pyplot as plt\r\nimport matplotlib as mpl\r\n\r\ndef axis():\r\n\tfig, ax = plt.subplots()\r\n\t# Etichetta X\r\n\tticklab = ax.xaxis.get_ticklabels()[0]\r\n\ttrans = ticklab.get_transform()\r\n\tax.xaxis.set_label_coords(5,0, transform=trans)\r\n\t# Etichetta Y\r\n\tticklab = ax.yaxis.get_ticklabels()[0]\r\n\ttrans = ticklab.get_transform()\r\n\tax.yaxis.set_label_coords(0,5, transform=trans)\r\n\r\n\tax.spines['left'].set_position('center')\r\n\tax.spines['bottom'].set_position('center')\r\n\tax.spines['right'].set_color('none')\r\n\tax.spines['top'].set_color('none')\r\n\tax.xaxis.tick_bottom()\r\n\tplt.axis([-6 , 6, -6, 6])\r\n\tplt.ylabel('Prezzo').set_color('gray')\r\n\tplt.xlabel('Quantit\u00e0').set_color('gray')\r\n\tplt.show()\r\n\r\naxis()<\/pre>\n
\"\"<\/a><\/p>\n
Adding some text on the screen<\/h2>\n
If you want to add some text like a legend with an arrow pointing to the point you need to explain what is it, you can use annotate.<\/p>\n
import matplotlib.pyplot as plt\r\nimport matplotlib as mpl\r\n\r\ndef axes(x,y):\r\n\tfig, ax = plt.subplots()\r\n\t# Etichetta X\r\n\tticklab = ax.xaxis.get_ticklabels()[0]\r\n\ttrans = ticklab.get_transform()\r\n\tax.xaxis.set_label_coords(5,0, transform=trans)\r\n\t# Etichetta Y\r\n\tticklab = ax.yaxis.get_ticklabels()[0]\r\n\ttrans = ticklab.get_transform()\r\n\tax.yaxis.set_label_coords(0,5, transform=trans)\r\n\r\n\t# arrows\r\n\tax.annotate(\"This is the origin\", xy=(0, 0), xytext=(0, 1), arrowprops=dict(arrowstyle=\"->\"))\r\n\r\n\tax.spines['left'].set_position('center')\r\n\tax.spines['bottom'].set_position('center')\r\n\tax.spines['right'].set_color('none')\r\n\tax.spines['top'].set_color('none')\r\n\tax.xaxis.tick_bottom()\r\n\tplt.axis([-6 , 6, -6, 6])\r\n\tplt.ylabel(x).set_color('gray')\r\n\tplt.xlabel(y).set_color('gray')\r\n\r\naxes(x = \"Price\", y=\"Quality\")\r\nif __name__ == \"__main__\":\r\n\tplt.show()\r\n<\/pre>\n
You will have this:<\/p>\n
\"\"<\/a><\/p>\n
Add a point<\/h2>\n
import matplotlib.pyplot as plt\r\nimport matplotlib as mpl\r\n\r\ndef axes(x,y):\r\n\tfig, ax = plt.subplots()\r\n\t# Etichetta X\r\n\tticklab = ax.xaxis.get_ticklabels()[0]\r\n\ttrans = ticklab.get_transform()\r\n\tax.xaxis.set_label_coords(5,0, transform=trans)\r\n\t# Etichetta Y\r\n\tticklab = ax.yaxis.get_ticklabels()[0]\r\n\ttrans = ticklab.get_transform()\r\n\tax.yaxis.set_label_coords(0,5, transform=trans)\r\n\r\n\t# arrows\r\n\t#ax.annotate(\"This is the origin\", xy=(0, 0), xytext=(0, 1), arrowprops=dict(arrowstyle=\"->\"))\r\n\r\n\tax.spines['left'].set_position('center')\r\n\tax.spines['bottom'].set_position('center')\r\n\tax.spines['right'].set_color('none')\r\n\tax.spines['top'].set_color('none')\r\n\tax.xaxis.tick_bottom()\r\n\tplt.axis([-6 , 6, -6, 6])\r\n\tplt.ylabel(x).set_color('gray')\r\n\tplt.xlabel(y).set_color('gray')\r\n\tplt.plot(1,1, 'ro')\r\n\r\naxes(x = \"Price\", y=\"Quality\")\r\nif __name__ == \"__main__\":\r\n\tplt.show()\r\n<\/pre>\n
\"\"<\/a><\/p>\n
<\/h2>\n
A different way<\/h2>\n
Let’s do something basic. Draw a point with some coordinates.<\/p>\n
import matplotlib.pyplot as plt\r\n\r\n\r\ndef point(axis=0):\r\n\tplt.plot([1], [1], 'ro')\r\n\tplt.ylabel('Prezzo')\r\n\tplt.xlabel('quantit\u00e0')\r\n\r\ndef axis():\r\n\tplt.plot([0,-6], [0, 0], 'k', lw=1)\r\n\tplt.plot([0,0], [0, 6], 'k', lw=1)\r\n\tplt.plot([0,0], [0, -6], 'k', lw=1)\r\n\tplt.plot([6,0], [0,0], 'k', lw=1)\r\n\tplt.axis([-6 , 6, -6, 6])\r\n\tplt.ylabel('Prezzo')\r\n\tplt.xlabel('Quantit\u00e0')\r\n\r\n\r\naxis()\r\npoint()\r\nplt.show()<\/pre>\n
The result is this:<\/p>\n
\"\"<\/a><\/p>\n
Color and size with color and markersize<\/h2>\n
This will change the size and the color of our dot.<\/p>\n
def point(axis=0):\r\n\tplt.plot([1], [1], 'ro', color='green', markersize=24)\r\n\tplt.ylabel('Prezzo')\r\n\tplt.xlabel('quantit\u00e0')<\/pre>\n
\"\"<\/a><\/p>\n
Let’s say we have this table<\/p>\n<\/table>
OFFERTA<\/td> Posti<\/td> Qualit\u00e0<\/td> Prezzi<\/td>
Ristorante Alba<\/td> 50<\/td> 0<\/td> -3<\/td>
Ristorante Baia<\/td> 60<\/td> 3<\/td> -2<\/td>
Ristorante Calice<\/td> 120<\/td> -4<\/td> -1<\/td>
Ristorante Delice<\/td> 50<\/td> -3<\/td> -2<\/td>
Ristorante Elena<\/td> 60<\/td> -4<\/td> -1<\/td>
Preferenze dei segmenti di clientela<\/table><\/table>\n
Now lets do something more fun<\/p>\n
import matplotlib.pyplot as plt\r\n\r\n\r\ndef point(name, size, x, y, color):\r\n\tplt.plot(x, y, 'ro', color=color, markersize=size\/2, alpha=0.7)\r\n\tplt.ylabel('Prezzo')\r\n\tplt.xlabel('quantit\u00e0')\r\n\tplt.annotate(name, xy=(x,y),bbox=dict(boxstyle='round,pad=0.5', fc='yellow', alpha=0.5))\r\n\r\ndef axis():\r\n\tplt.plot([0,-6], [0, 0], 'k', lw=1)\r\n\tplt.plot([0,0], [0, 6], 'k', lw=1)\r\n\tplt.plot([0,0], [0, -6], 'k', lw=1)\r\n\tplt.plot([6,0], [0,0], 'k', lw=1)\r\n\tplt.axis([-6 , 6, -6, 6])\r\n\tplt.ylabel('Prezzo')\r\n\tplt.xlabel('Quantit\u00e0')\r\n\r\na = \"\"\"\r\nRistorante Alba\t50\t-3\t3\r\nRistorante Baia\t90\t3\t1\r\nRistorante Calice\t90\t-1\t-3\r\nRistorante Delice\t50\t3\t4\r\nRistorante Elena\t120\t3\t-4\r\n\"\"\"\r\n\r\nb = \"\"\"\r\n\"Privati\"\t40\t[0]\t[2]\r\n\"Banchetti\"\t40\t[2]\t[-4]\r\n\"Turisti\"\t20\t[1]\t[0]\r\n\"\"\"\r\n\r\n\r\ndef list_it(a):\r\n\ta = a.replace(\"\\\"\",\"\").replace(\"[\",\"\").replace(\"]\",\"\")\r\n\ta = a.splitlines()[1:]\r\n\tfor n,x in enumerate(a):\r\n\t\ta[n] = a[n].split()\r\n\treturn a\r\na = list_it(a)\r\nb = list_it(b)\r\n\r\n\r\naxis()\r\n\r\nfor r in a:\r\n\tpoint(r[1], int(r[2]), int(r[3]), int(r[4]), 'green')\r\nfor r in b:\r\n\tpoint(r[0], int(r[1])*2.5, int(r[2]), int(r[3]), 'orange')\r\n\r\n\r\nplt.show()\r\n<\/pre>\n
\"\"<\/a><\/p>\n
More graphs<\/h2>\n
With this code we can add more data for more situations, creating one graph for each data. If some data are in the same spot, they will show in the same label the names that share the same spot.<\/p>\n
import matplotlib.pyplot as plt\r\nfrom random import random\r\n\r\ndef axes(x,y, name):\r\n\tfig, ax = plt.subplots()\r\n\t# Etichetta X\r\n\tax.set_title(name)\r\n\tax.ticklabel_format(axis='both', style='plain', scilimits=(0,0))\r\n\tticklab = ax.xaxis.get_ticklabels()[0]\r\n\ttrans = ticklab.get_transform()\r\n\tax.xaxis.set_label_coords(5,0, transform=trans)\r\n\t# Etichetta Y\r\n\tticklab = ax.yaxis.get_ticklabels()[0]\r\n\ttrans = ticklab.get_transform()\r\n\tax.yaxis.set_label_coords(0,5, transform=trans)\r\n\r\n\t# arrow\r\n\t#ax.annotate(\"This is the origin\", xy=(0, 0), xytext=(0, 1), arrowprops=dict(arrowstyle=\"->\"))\r\n\r\n\tax.spines['left'].set_position('center')\r\n\tax.spines['bottom'].set_position('center')\r\n\tax.spines['right'].set_color('none')\r\n\tax.spines['top'].set_color('none')\r\n\tax.xaxis.tick_bottom()\r\n\taxis = [-6, 6, -6, 6]\r\n\tplt.axis(axis, axis*2)\r\n\t#plt.yticks(axis, [\"a\",\"b\",\"c\", \"d\"] )#(-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6))\r\n\tplt.ylabel(x).set_color('gray')\r\n\tplt.xlabel(y).set_color('gray')\r\n\r\ndef annotate(name, x, y):\r\n\tplt.annotate(name, xy=(x,y),bbox=dict(boxstyle='round,pad=0.1', fc='green', alpha=0.7))\r\n\r\ndef annotate2(name, x, y):\r\n\tplt.annotate(name, xy=(x,y),bbox=dict(boxstyle='round,pad=0.3', fc='yellow', alpha=0.7))\r\n\r\ndef point(name, size, x, y, color):\r\n\tplt.plot(x, y, 'ro', color=color, markersize=size\/2, alpha=0.7)\r\n\tfor t in xy:\r\n\t\tif [x,y] == t[0]:\r\n\t\t\tif name not in name:\r\n\t\t\t\tname = name + \" e \" + t[1]\r\n\txy.append([[x,y], name])\r\n\tif \"Conc\" not in name:\r\n\t\tname = \"Conc.:\" + name\r\n\tannotate(name, x, y)\r\nxy = []\r\ndef point2(name, size, x, y, color):\r\n\tplt.plot(x, y, 'ro', color=color, markersize=size, alpha=0.7)\r\n\tfor t in xy:\r\n\t\tif [x,y] == t[0]:\r\n\t\t\tname = name + \" - \" + t[1]\r\n\txy.append([[x,y], name])\r\n\tif \"Targ:\" not in name:\r\n\t\tname = \"Targ.:\" + name\r\n\tannotate2(name,x,y)\r\n\r\n\r\nclass Alunni:\r\n\tdict = {}\r\n\tdef __init__(self, name, offerta, domanda):\r\n\t\tself.name = name\r\n\t\tself.offerta = offerta\r\n\t\tself.domanda = domanda\r\n\t\tAlunni.dict[name] = self\r\n\r\n\r\n\r\n\r\ndef list_it(a):\r\n\ta = a.replace(\"\\\"\",\"\").replace(\"[\",\"\").replace(\"]\",\"\")\r\n\ta = a.splitlines()[1:]\r\n\tfor n,x in enumerate(a):\r\n\t\ta[n] = a[n].split()\r\n\treturn a\r\n# ========================= alunni =====================\r\nAma_restaurant = Alunni(\"AMA\",\r\n\"\"\"\r\nRistorante Alba\t    50\t0\t-3\r\nRistorante Baia\t    60\t3\t-2\r\nRistorante Calice\t120\t-4\t-1\r\nRistorante Delice\t50\t-3\t-2\r\nRistorante Elena\t60\t-4\t-1\r\n\"\"\",\r\n\r\n\"\"\"\r\n\"Privati\"\t25\t[-4] [-1]\r\n\"Banchetti\"\t25\t[2]\t [2]\r\n\"Turisti\"\t50\t[3]\t [0]\r\n\"\"\")\r\n\r\nBort_restaurant = Alunni(\"BORT\",\r\n\t\"\"\"\r\nRistorante Alba\t90\t0\t0\r\nRistorante Baia\t120\t-1\t-3\r\nRistorante Calice\t70\t1\t4\r\nRistorante Delice\t90\t-2\t2\r\nRistorante Elena\t50\t1\t1\r\n\"\"\",\r\n\"\"\"\r\n\"Privati\"\t40\t[-1]\t[-4]\r\n\"Banchetti\"\t25\t[-1]\t[-4]\r\n\"Turisti\"\t35\t[-2]\t[0]\r\n\"\"\"\r\n)\r\n# ========================================================\r\n\r\n\r\ndef start(name, o, d):\r\n\tglobal a,b\r\n\tnome, a,b = name, o, d\r\n\ta = list_it(a)\r\n\tb = list_it(b)\r\n\taxes(x=\"Prezzo\", y=\"Qualit\u00e0\", name=nome)\r\n\tfor r in a:\r\n\t\tpoint(r[1], int(r[2]), int(r[3]), int(r[4]), 'blue')\r\n\tfor r in b:\r\n\t\tpoint2(r[0], int(r[1])*2.5, int(r[2]), int(r[3]), 'orange')\r\n\r\nfor k in Alunni.dict:\r\n\tstart(Alunni.dict[k].name, Alunni.dict[k].offerta, Alunni.dict[k].domanda)\r\n\txy = []\r\nplt.show()\r\n<\/pre>\n
\"\"<\/a> \"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"Let’s see how to make a graph with matplotlib in the easiest way: draw a plot on a cartesian graph.\n [...]<\/a>","protected":false},"author":1,"featured_media":1596,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_crdt_document":"","footnotes":""},"categories":[1,324],"tags":[326,325],"class_list":["post-1591","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-examples","category-matplotlib","tag-graph","tag-matplotlib"],"avopt_banners_inside_post":true,"avopt_banners_on_page":true,"av_copy_from":"","av_sharing_message":"","av_sharing_allowed":false,"av_sharing_on":{"fb":[],"tw":[]},"av_allow_affiliate_banner":false,"av_allow_affiliate_multi_banner":false,"av_show_affiliation_buy_button":false,"av_post_rating":true,"av_have_post_rating_value":false,"av_is_artificial_intelligence_content":false,"_links":{"self":[{"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/posts\/1591","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/comments?post=1591"}],"version-history":[{"count":8,"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/posts\/1591\/revisions"}],"predecessor-version":[{"id":1616,"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/posts\/1591\/revisions\/1616"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/media\/1596"}],"wp:attachment":[{"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/media?parent=1591"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/categories?post=1591"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pythonprogramming.altervista.org\/wp-json\/wp\/v2\/tags?post=1591"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
DOMANDA<\/td> Qualit\u00e0<\/td> Prezzi<\/td>
\"Privati\"<\/td> 25 <\/td>[-4]<\/td> [-1]<\/td>
\"Banchetti\"<\/td> 25<\/td> [2]<\/td> [2]<\/td>
\"Turisti\"<\/td> 50<\/td> [3]<\/td> [0]<\/td>