重新梳理Python基础（5）

这个系列的博客是学习《Learn Python the Hard Way》中做的笔记。

1. 由于今天需要看的five chapters是复习性质的内容，把前边的内容综合了一下，所以没有新内容

只把代码贴在这

print "Let's practice everything."
print "You\'d need to know \'bout escapes with \\ that do \n newlines and \t tabs."

poem = """
\t The lovely word
with logic so firmly planted
cannot discern \n the needs of love
nor comprehend passion from intuition
and requires an explanation
\n\t\twhere there is none.
"""

print "-------------------"
print poem
print "-------------------"

five = 10 - 2 + 3 -6
print "This should be five: %s" % five

def secret_formula(started):
    jelly_beans = started * 500
    jars = jelly_beans / 1000
    crates = jars / 100
    return jelly_beans, jars, crates

start_point = 10000
beans, jars, crates = secret_formula(start_point)

print "With a starting point of: %d" % start_point
print "We'd have %d beans, %d jars, and %d crates." % (beans, jars, crates)

start_point = start_point / 10

print "We can also do that this way:"
print "We'd have %d beans, %d jars, and %d crates." % secret_formula(start_point)

输出

E:\SkyDrive\python\the hard way to learn python>python ex24.py
Let's practice everything.
You'd need to know 'bout escapes with \ that do
 newlines and    tabs.
-------------------

         The lovely word
with logic so firmly planted
cannot discern
 the needs of love
nor comprehend passion from intuition
and requires an explanation

                where there is none.

-------------------
This should be five: 5
With a starting point of: 10000
We'd have 5000000 beans, 5000 jars, and 50 crates.
We can also do that this way:
We'd have 500000 beans, 500 jars, and 5 crates.

2. 把自己写的函数放在一个文件里，然后import这个文件，即可在代码里使用这些函数

把函数放在ex25.py这个文件里

def break_words(stuff):
    """This function will break up words for us."""
    words = stuff.split(" ")
    return words

def sort_words(words):
    """Sorts the words."""
    return sorted(words)

def print_first_word(words):
    """Prints the first word after popping it off."""
    word = words.pop(0)
    print word

def print_last_word(words):
    """Prints the last word after popping it off."""
    word = words.pop(-1)
    print word

def sort_sentence(sentence):
    """Takes in a full sentence and returns the sorted words."""
    words = break_words(sentence)
    return sort_words(words)

def print_first_and_last(sentence):
    """Prints the first and last words of the sentence."""
    words = break_words(sentence)
    print_first_word(words)
    print_last_word(words)

def print_first_and_last_sorted(sentence):
    """Sorts the words then Prints the first and last one."""
    words = sort_sentence(sentence)
    print_first_word(words)
    print_last_word(words)

在python命令行里执行如下命令

E:\SkyDrive\python\the hard way to learn python>python ex25.py

E:\SkyDrive\python\the hard way to learn python>python
Python 2.7.3 (default, Apr 10 2012, 23:24:47) [MSC v.1500 64 bit (AMD64)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>> import ex25
>>> sentence = "All good things come to those who wait."
>>> words = ex25.break_words(sentence)  #使用ex25里的函数需要这样。如果嫌麻烦，可以在开始from ex25 import *，这样这行就可以这么写words = break_words(sentence)
>>> words
['All', 'good', 'things', 'come', 'to', 'those', 'who', 'wait.']
>>> sorted_words = ex25.sort_words(words)
>>> sorted_words
['All', 'come', 'good', 'things', 'those', 'to', 'wait.', 'who']
>>> ex25.print_first_word(words)
All
>>> ex25.print_last_word(words)
wait.
>>> wrods
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'wrods' is not defined
>>> words
['good', 'things', 'come', 'to', 'those', 'who']
>>> ex25.print_first_word(sorted_words)
All
>>> ex25.print_last_word(sorted_words)
who
>>> sorted_words
['come', 'good', 'things', 'those', 'to', 'wait.']
>>> sorted_words = ex25.sort_sentence(sentence)
>>> sorted_words
['All', 'come', 'good', 'things', 'those', 'to', 'wait.', 'who']
>>> ex25.print_first_and_last(sentence)
All
wait.

值得注意的是两点

• import ex25和from ex25 import *的区别，调用函数ex25.break_words(sentence)和直接调用break_words(sentence)
• list可以pop任意位置