模块urlib.request未获取数据

Question

我正在尝试使用Python 3从lynda测试这个演示程序。我正在使用Pycharm作为我的IDE。我已经添加并安装了请求包，但当我运行该程序时，它运行得很干净，并显示一条消息"Process finished with exit code 0"，但不显示print语句的任何输出。我哪里错了？

import urllib.request # instead of urllib2 like in Python 2.7
import json

def printResults(data):
    # Use the json module to load the string data into a dictionary
    theJSON = json.loads(data)
    # now we can access the contents of the JSON like any other Python object
    if "title" in theJSON["metadata"]:
        print(theJSON["metadata"]["title"])
    # output the number of events, plus the magnitude and each event name
    count = theJSON["metadata"]["count"];
    print(str(count) + " events recorded")
    # for each event, print the place where it occurred
    for i in theJSON["features"]:
        print(i["properties"]["place"])
    # print the events that only have a magnitude greater than 4
    for i in theJSON["features"]:
        if i["properties"]["mag"] >= 4.0:
            print("%2.1f" % i["properties"]["mag"], i["properties"]["place"])
    # print only the events where at least 1 person reported feeling something
    print("Events that were felt:")
    for i in theJSON["features"]:
        feltReports = i["properties"]["felt"]
        if feltReports != None:
            if feltReports > 0:
                print("%2.1f" % i["properties"]["mag"], i["properties"]["place"], " reported " + str(feltReports) + " times")
    # Open the URL and read the data
    urlData = "http://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_day.geojson"
    webUrl = urllib.request.urlopen(urlData)
    print(webUrl.getcode())
    if webUrl.getcode() == 200:
        data = webUrl.read()
        data = data.decode("utf-8") # in Python 3.x we need to explicitly decode the response to a string
    # print out our customized results
        printResults(data)
    else:
        print("Received an error from server, cannot retrieve results " + str(webUrl.getcode()))

Answer 1

不确定您是否故意忽略了这一点，但该脚本实际上并没有执行导入和函数定义之外的任何代码。假设你不是故意遗漏的，那么你需要在文件的末尾写下以下内容。

if __name__ == '__main__':
    data = "" # your data
    printResults(data)

对__name__等于"__main__"的检查只是为了让您的代码只有在显式运行文件时才执行。要在文件被访问时始终运行printResults(data)函数（比如，如果它被导入到另一个模块中），你可以在文件底部这样调用它：

data = "" # your data
printResults(data)

Answer 2

您的评论是：必须重新启动IDE，这让我认为pycharm可能无法自动检测新安装的python包。这个SO的答案似乎提供了一个解决方案。

SO应答