创建解析器代码

Question

我对 python 完全陌生，之前从未使用过它。我被困在这个程序上，它被认为是一个命令行程序，它要求输入关键字，然后在可用标题列表中搜索它们。我使用 json 将 api 的信息加载到字典中并能够搜索它。

我的主要问题是我不知道如何使用 argparser 来使它成为一个命令行程序。

帮忙？

到目前为止，这是我的代码：

import requests
import argparse
import json
from urllib.request import urlopen


def create_json_file_from_api(url):
    request = urlopen(url)
    data = request.read().decode("utf-8")
    j_data = json.loads(data)
    return j_data


json_data = create_json_file_from_api("http://hn.algolia.com/api/v1/search_by_date?tags=story&numericFilters=created_at_i>1488196800,created_at_i<1488715200")
print(json_data) #making sure the data pulled is correct

def _build_array_of_necessary_data(data, d=[]):
    if 'hits' in data:
        for t in data['hits']:
            d.append({'title' : t.get('title'), 'points': t.get('points'), 'url' : t.get('url')})
            _build_array_of_necessary_data(t,d)
    return d

j = _build_array_of_necessary_data(json_data)
print(j) #testing the function above
def _search_titles_for_keywords(data, word, s=[]):
    for c in data:
        if word in c['title']:
            s.append({'title' : c.get('title')})
    return s

word = "the" #needs to be input by user
word.upper() == word.lower()
k = _search_titles_for_keywords(j, word)
print(k) #testing the function above

def _search_links_for_point_value(data, points, s=[]):
    points = int(points)

    for c in data:
        if points <= c['points']:
            s.append({'Title of article is' : c.get('title')})
    return s

points = "7" #needs to be input by user
l = _search_links_for_point_value(j, points)

print(l)

Answer 1

只需更改设置点的行以询问用户输入

points = input("Enter points ")

然后您的程序将要求用户提供积分。虽然这没有使用 argparser。当您的脚本因更多输入选项等而变得复杂时，您可以查看 argparser。 https://docs.python.org/3/library/argparse.html

Answer 2

要使用 argparse，您首先需要声明 ArgumentParser 对象，然后您可以使用 add_argument() 方法向该对象添加参数。在此之后，您可以使用 parse_args() 方法来解析命令行参数。

作为使用您的程序的示例：

import argparse

parser = argparse.ArgumentParser()
parser.add_argument("word", help="the string to be searched")
# you will want to set the type to int here as by default argparse parses all of the arguments as strings
parser.add_argument("point", type = int)
args = parser.parse_args()
word = args.word
point = args.point

在这种情况下，您将按照添加命令的相同顺序从命令行调用它，因此在您的情况下 python your_program.py the 7

有关详细信息，请参阅：https://docs.python.org/3/howto/argparse.html

Answer 3

如果你想运行将其作为带参数的python脚本，你需要

if __name__ == '__main__':
    ...

告诉 python 到运行接下来的内容。通过将 'word' 参数与 -w 或 --word 标志一起传递，以及将 'points' 参数与 -p 或 --points 标志。示例：

C:\Users\username\Documents\> python jsonparser.py -w xerox -p 2
or
C:\Users\username\Documents\> python jsonparser.py --points 3 --word hello

重构代码如下：

import argparse
from sys import argv
import json
from urllib.request import urlopen


def create_json_file_from_api(url):
    request = urlopen(url)
    data = request.read().decode("utf-8")
    j_data = json.loads(data)
    return j_data

def _build_array_of_necessary_data(data, d=[]):
    if 'hits' in data:
        for t in data['hits']:
            d.append({'title' : t.get('title'), 'points': t.get('points'), 'url' : t.get('url')})
            _build_array_of_necessary_data(t,d)
    return d

def _search_titles_for_keywords(data, word, s=[]):
    for c in data:
        if word in c['title'].lower():
            s.append({'title' : c.get('title')})
    return s

def _search_links_for_point_value(data, points, s=[]):
    points = int(points)

    for c in data:
        if points <= c['points']:
            s.append({'Title of article is' : c.get('title')})
    return s


if __name__ == '__main__':
    # create an argument parser, add argument with flags
    parser = argparse.ArgumentParser(description='Search JSON data for `word` and `points`')
    parser.add_argument('-w', '--word', type=str, required=True, 
        help='The keyword to search for in the titles.')
    parser.add_argument('-p', '--points', type=int, required=True, 
        help='The points value to search for in the links.')
    # parse the argument line
    params = parser.parse_args(argv[1:])

    url = "http://hn.algolia.com/api/v1/search_by_date?tags=story&numericFilters=created_at_i%3E1488196800,created_at_i%3C1488715200"
    json_data = create_json_file_from_api(url)
    print(json_data[:200]) #making sure the data pulled is correct

    j = _build_array_of_necessary_data(json_data)
    print(j) #testing the function above

    k = _search_titles_for_keywords(j, params.word.lower())
    print(k) #testing the function above

    l = _search_links_for_point_value(j, params.points)
    print(l)

创建解析器代码

Create Parser code

python

json

argparse