好的，我想做的就是制作一份关于世界各国人口的精美条形图。
pop_list = pd.read_table('country.dat', names=cols)
pop_list.dtypes
# Rank int64
# Country object
# Population object
print(type(pop_list['Population']))
pd.Series.hist(pop_list['Population'])
给出错误： TypeError：unorderable类型：str（）＆lt;浮动（）
pop_list.plot.hist(['Population'],alpha=0.5)
plt.show()
制作垃圾情节，大概是'Rank'，最后是
pop_list['Population'].plot().hist()
给出： TypeError：清空'DataFrame'：没有要绘制的数字数据
答案 0 :(得分：1)
data回答不同后 - 需要参数var haveLoadedMetadata = stream => {
let preview = document.createElement("video");
preview.srcObject = stream;
return new Promise(resolve => preview.onloadedmetadata = resolve);
};
var start = ms => navigator.mediaDevices.getUserMedia({video: true})
.then(stream => haveLoadedMetadata(stream)
.then(() => record(stream, ms))
.then(recording => {
stop(stream);
video.src = link.href = URL.createObjectURL(new Blob(recording));
link.download = "recording.webm";
link.innerHTML = "Download recording";
log("Playing "+ recording[0].type +" recording:");
}))
.catch(log);
var record = (stream, ms) => {
var rec = new MediaRecorder(stream), data = [];
rec.ondataavailable = e => data.push(e.data);
rec.start();
log(rec.state + " for "+ (ms / 1000) +" seconds...");
var stopped = new Promise((y, n) => (rec.onstop = y, rec.onerror = e => n(e.error || e.name)));
return Promise.all([stopped, wait(ms).then(() => rec.stop())])
.then(() => data);
};
var stop = stream => stream.getTracks().forEach(track => track.stop());
var wait = ms => new Promise(resolve => setTimeout(resolve, ms));
var log = msg => div.innerHTML += "<br>" + msg;：
<button onclick="start(1000)">Record 1 second!</button>
<div id="div"></div><br>
<video id="video" height="120" width="160" autoplay></video>
<a id="link"></a>