用字典树实现字频统计。

article.txt

9 Mac OS X Port Command Examples to Install and Update Packages

by Sanjay Kumar, thegeekstuff.comJanuary 23
Port is a terminal command utility which is used to update open source software on Mac OS X.

The port command is bundled as part of MacPorts Framework.

You can install port command either by downloading and installing the binary version for your corresponding Mac OS X, or by downloading the source code and compiling it on your OS X version.

The binary file of MacPorts for various version of OSX are available here. Once you download the binary version, just click on the package to install it. You should have administrator right on your system to install it. X-code is pre-req for MacPorts. If you don’t have X-code on your system, it will display a warning message.

Update Port List using selfupdate
Immediately after you install the port command, you should update the available port list by doing a selfupdate as shown below.

If you are behind the proxy, you need to add the following lines to /etc/sudoers file as sudoer before you perform selfupdate:

Defaults env keep += "HTTP PROXY HTTPS PROXY FTP PROXY RSYNC PROXY"
Defaults env keep += "ALL PROXY NO PROXY"
Add the following lines to your .bashrc at your home folder to get port connect from behind a proxy

2. Upgrade All Outdated Packages
After selfupdate it will ask you to do port upgrade for all outdated installed ports. You can upgrade all outdated packages using “upgrade outdated” option as shown below.

3. Search for a Specific Package
You can search for a specific package by using a keyword. This will search for all available packages with the given keyword, and display the corresponding version number of the available packages also.

The following will search and list all packages that contains the keyword “tmux” either in package name or description as shown below.

4. Install a Specific Package
On you searched for a specific package, you can install it using “install” option as shown below.

When you install a package, it displays all the dependent packages, and install them one by one before installing the given package.

The following will install tmux package. As shown below, it will also install the dependent package “libevent” first, before installing tmux.

5. View Dependent Packages

If you just want to view all the dependent packages before installing a package, you can do it using deps option as shown below.

This is also helpful to view the dependencies of a package that is already installed.

The following will display all the dependent packages for tmux. As you see below, tmux is dependent on libevent and ncurses packages.

6. Uninstall a Package

To uninstall a package, use the uninstall option as shown below. When you uninstall a package, it will not remove the dependencies, it will uninstall only the given package.

The following will uninstall the htop package.

7. Uninstall All Old Packages

You can uninstall all old versions of the packages that are not being used now using the “uninstall inacative” option as shown below. Use the -f option also, which will force uninstall all inactive packages as shown below.

8. Delete Downloads of Installed Packages

When you install a package, it downloads the package and then installs it on your system. Once the package is installed, the downloaded file takes-up unnecessary disk space on your system. So, it is a good idea to delete all these downloaded packages once in a while using the “clean -all installed” option.

The following will delete all downloaded packages that are used during installation, but not required anymore, as they are already installed.

9. Delete Downloads of All Packages
Sometimes you might’ve downloaded a package, but not installed it on your system yet. You can delete all downloads irrespective of whether they are already installed or not on your system using “clean -all all” option as shown below.

The following will delete all downloaded packages (both installed and not-installed).

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trie_word_count.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-


class Trie_tree():
    def __init__(self):
        # node = [father, child, keep_char, word_count]
        self._root = [None, [], None, 0]

    def insert(self, word):
        current_word = word
        current_node = self._root
        self._insert_operation_1(current_word, current_node)

    def _insert_operation_1(self, current_word, current_node):
        if current_word != "":
            first_char = current_word[0]
            child_node = current_node[1]
            is_in_child_node = False

            for node in child_node:
                if first_char == node[2]:
                    is_in_child_node = True
                    current_word = current_word[1:]
                    current_node = node
                    self._insert_operation_1(current_word, current_node)
                    break
                else:
                    continue

            if not is_in_child_node:
                self._insert_operation_2(current_word, current_node)

        else:
            current_node[3] += 1

    def _insert_operation_2(self, current_word, current_node):
        first_char = current_word[0]

        # creat a new node and insert it in the tree
        new_node = [None, [], None, 0]
        new_node[2] = first_char
        new_node[0] = current_node
        current_node[1].append(new_node)

        current_word = current_word[1:]
        if current_word != "":
            current_node = new_node
            self._insert_operation_2(current_word, current_node)

        else:
            new_node[3] += 1

    def find(self, word):
        current_word = word
        current_node = self._root
        return self._find_opration(current_word, current_node)

    def _find_opration(self, current_word, current_node):
        if current_word != "":
            first_char = current_word[0]
            child_node = current_node[1]

            if child_node == []:
                return 0

            is_in_child_node = False
            for node in child_node:
                if first_char == node[2]:
                    is_in_child_node = True
                    current_word = current_word[1:]
                    current_node = node
                    return self._find_opration(current_word, current_node)

                else:
                    continue

            if not is_in_child_node:
                return 0
        else:
            return current_node[3]

if __name__ == "__main__":
    import re
    demo_trie = Trie_tree()
    print "--------Build the tree--------"

    with open("article.txt", "r") as content:
        for line in content:
            for word in re.split(r"[\s\W]+", line):
                if word == "":
                    break
                if not word.isdigit():
                    demo_trie.insert(word.lower())
                else:
                    pass

    print "-------Count word test:-------"
    print "all      :", demo_trie.find("all")
    print "is       :", demo_trie.find("is")
    print "good     :", demo_trie.find("good")
    print "packages :", demo_trie.find("packages")