Started solving chapter 11

Author: LambdaDrive

Chapter 11/Exercise11_1.py

@@ -0,0 +1,11 @@
+from urllib.request import urlopen
+def news(url, words):
+    response = urlopen(url)
+    html = response.read()
+    html = html.decode()
+    word = []
+    for wor in words:
+        word.append([wor, html.count(wor)])
+    for couple in word:
+        print ('{} appears {} times.'.format(couple[0], couple[1]))
+    

Chapter 11/Exercise11_2.py

@@ -0,0 +1,19 @@
+from html.parser import HTMLParser
+class MyHTMLParser(HTMLParser):
+
+    def __init__(self):
+        HTMLParser.__init__(self)
+        self.space = 0
+    
+    def handle_starttag(self, tag, attrs):
+
+        if tag not in {'br', 'p'}:
+            print('{} {} start'.format(' ' *self.space, tag))
+            self.space += 4
+        
+    def handle_endtag(self, tag):
+
+        if tag not in {'br', 'p'}:
+            self.space -= 4
+            print('{} {} end'.format(' ' *self.space, tag))
+            

Chapter 11/ch11.py

@@ -0,0 +1,126 @@
+from urllib.request import urlopen
+def getSource(url):
+    'returns the content of resource specified by url as a string'
+    response = urlopen(url)
+    html = response.read()
+    return html.decode()
+
+
+
+from html.parser import HTMLParser
+class LinkParser(HTMLParser):
+    '''HTML doc parser that prints values of
+       href attributes in anchor start tags'''
+
+    def handle_starttag(self, tag, attrs):
+        'print value of href attribute if any'
+        
+        if tag == 'a':                      # if anchor tag
+
+            # search for href attribute and print its value
+            for attr in attrs:
+                if attr[0] == 'href':
+                    print(attr[1])
+
+
+
+from urllib.parse import urljoin
+from html.parser import HTMLParser
+class Collector(HTMLParser):
+    'collects hyperlink URLs into a list'
+
+    def __init__(self, url):
+        'initializes parser, the url, and a list'
+        HTMLParser.__init__(self)
+        self.url = url
+        self.links = []
+
+        # Solution to Practice Problem 11.3        
+        self.text = ''
+        
+    def handle_starttag(self, tag, attrs):
+        'collects hyperlink URLs in their absolute format'
+        if tag == 'a':
+            for attr in attrs:
+                if attr[0] == 'href':
+                    # construct absolute URL
+                    absolute = urljoin(self.url, attr[1])
+                    if absolute[:4] == 'http': # collect HTTP URLs
+                        self.links.append(absolute)
+                        
+    # Solution to Practice Problem 11.3        
+    def handle_data(self, data):
+        'collects and concatenates text data'
+        self.text += data
+
+    def getLinks(self):
+        'returns hyperlinks URLs in their absolute format'
+        return self.links
+
+    # Solution to Practice Problem 11.3
+    def getData(self):
+        'returns the concatenation of all text data'
+        return self.text
+
+
+
+##################################
+# Solutions to Practice Problems #
+##################################
+
+
+# Practice Problem 11.1
+from urllib.request import urlopen
+def news(url, topics):
+    '''counts in resource with URL url the frequency
+       of each topic in list topics'''
+    # download and decode resource to obtain all lowercase content
+    response = urlopen(url)
+    html = response.read()
+    content = html.decode().lower()
+
+    for topic in topics: # find frequency of topic in content
+        n = content.count(topic)
+        print('{} appears {} times.'.format(topic, n))
+
+
+# Practice Problem 11.2
+from html.parser import HTMLParser
+class MyHTMLParser(HTMLParser):
+    'HTML doc parser that prints tags indented by depth'
+    
+    def __init__(self):
+        'initializes the parser and the initial indentation'
+        HTMLParser.__init__(self)
+        self.indent = 0            # initial indentation value
+
+    def handle_starttag(self, tag, attrs):
+        '''prints start tag with an indentation proportional
+           to the depth of the tag's element in the document'''
+        if tag not in {'br', 'p'}:
+            print('{}{} start'.format(self.indent*' ', tag))
+            self.indent += 4
+
+    def handle_endtag(self, tag):
+        '''prints end tag with an indentation proportional
+           to the depth of the tag's element in the document'''
+        if tag not in {'br','p'}:
+            self.indent -= 4
+            print('{}{} end'.format(self.indent*' ', tag))
+
+
+# Practice Problem 11.6
+from re import findall
+def frequency(content):
+    '''returns dictionary containing frequencies
+       of words in string content'''
+    pattern = '[a-zA-Z]+'
+    words = findall(pattern, content)
+    dictionary = {}
+    for w in words:
+        if w in dictionary:
+            dictionary[w] +=1
+        else:
+            dictionary[w] = 1
+    return dictionary
+