<ruby id="bdb3f"></ruby>

    <p id="bdb3f"><cite id="bdb3f"></cite></p>

      <p id="bdb3f"><cite id="bdb3f"><th id="bdb3f"></th></cite></p><p id="bdb3f"></p>
        <p id="bdb3f"><cite id="bdb3f"></cite></p>

          <pre id="bdb3f"></pre>
          <pre id="bdb3f"><del id="bdb3f"><thead id="bdb3f"></thead></del></pre>

          <ruby id="bdb3f"><mark id="bdb3f"></mark></ruby><ruby id="bdb3f"></ruby>
          <pre id="bdb3f"><pre id="bdb3f"><mark id="bdb3f"></mark></pre></pre><output id="bdb3f"></output><p id="bdb3f"></p><p id="bdb3f"></p>

          <pre id="bdb3f"><del id="bdb3f"><progress id="bdb3f"></progress></del></pre>

                <ruby id="bdb3f"></ruby>

                合規國際互聯網加速 OSASE為企業客戶提供高速穩定SD-WAN國際加速解決方案。 廣告
                ## **爬取當當前500數據-如何設計一個完整的請求程序** 實戰:爬取當當網 Top 500 本五星好評書籍 #url樣式 [http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-1](http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-1) ...... [http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-3](http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-3) ...... [http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-25](http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-25) <span style="color:red;">1.首次嘗試</span> ~~~ import requests import random url = "http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-1" user_agent_list =[ "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; en) Opera 9.50", "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko", "Mozilla/4.0 (compatible; MSIE 6.0; ) Opera/UCWEB7.0.2.37/28/999", ] header = { "User-Agent":random.choice(user_agent_list) } print(header) response = requests.get(url,headers=header) print(response.status_code) print(response.text) ~~~ <span style="color:red;">2.二次改進循環遍歷獲取全部</span> ~~~ import requests import random user_agent_list =[ "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; en) Opera 9.50", "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko", "Mozilla/4.0 (compatible; MSIE 6.0; ) Opera/UCWEB7.0.2.37/28/999", ] for x in range(26): url = "http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-{}" header = { "User-Agent": random.choice(user_agent_list) } print(header) url = url.format(x) print(url) response = requests.get(url,headers=header) print(response.status_code) ~~~ <span style="color:red;">3.三次改進,增加捕獲異常,增加時間等待</span> ~~~ import requests import random user_agent_list =[ "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; en) Opera 9.50", "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko", "Mozilla/4.0 (compatible; MSIE 6.0; ) Opera/UCWEB7.0.2.37/28/999", ] for x in range(26): url = "http://bang.dangdang.com/books/fivestars/01.00.00.00.00.00-recent30-0-0-1-{}" header = { "User-Agent": random.choice(user_agent_list) } print(header) url = url.format(x) print(url) #對請求做錯誤兼容,這樣就不會造成程序的異常終止 try: response = requests.get(url,headers=header) except Exception as e: print(e) # 打印錯誤 continue print(response.status_code) ~~~ <span style="color:red;">4.知識點</span> 1.Python2.6 開始,新增了一種格式化字符串的函數str.format(),它增強了字符串格式化的功能。 基本語法是通過{},和:來代替以前的%。 例如: ~~~ res = "{} {}".format("hello", "world") # 不設置指定位置,按默認順序 print(res) hello world ~~~ ~~~ res = "{0} {1}".format("hello", "world") # 設置指定位置 print(res) 'hello world' ~~~ ~~~ res = "{1} {0} {1}".format("hello", "world") # 設置指定位置 print(res) 'world hello world' ~~~ ~~~ res = "我叫:{name}, 我家在 {add}".format( add="Shanxi",name="sunyuwei") print(res) ~~~ 2. try-except異常處理 參考網址: [https://www.runoob.com/python/python-exceptions.html](https://www.runoob.com/python/python-exceptions.html) ~~~ try: 正常的操作 ...................... except: 發生異常,執行這塊代碼 ...................... else: 如果沒有異常執行這塊代碼 ~~~ 3.try-finally 語句 try-finally 語句無論是否發生異常都將執行最后的代碼。 ~~~ try: 正常的操作 ...................... finally: 無論是否發生異常,都執行這塊代碼 ...................... ~~~
                  <ruby id="bdb3f"></ruby>

                  <p id="bdb3f"><cite id="bdb3f"></cite></p>

                    <p id="bdb3f"><cite id="bdb3f"><th id="bdb3f"></th></cite></p><p id="bdb3f"></p>
                      <p id="bdb3f"><cite id="bdb3f"></cite></p>

                        <pre id="bdb3f"></pre>
                        <pre id="bdb3f"><del id="bdb3f"><thead id="bdb3f"></thead></del></pre>

                        <ruby id="bdb3f"><mark id="bdb3f"></mark></ruby><ruby id="bdb3f"></ruby>
                        <pre id="bdb3f"><pre id="bdb3f"><mark id="bdb3f"></mark></pre></pre><output id="bdb3f"></output><p id="bdb3f"></p><p id="bdb3f"></p>

                        <pre id="bdb3f"><del id="bdb3f"><progress id="bdb3f"></progress></del></pre>

                              <ruby id="bdb3f"></ruby>

                              哎呀哎呀视频在线观看