随笔分类 -  Python Learning

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User-defined types
摘要：We have used many of Python’s built-in types; now we are going to define a new type. As an example, we will create a type called Point that represents... 阅读全文
posted @ 2014-09-23 22:35 平静缓和用胸音说爱 阅读(289) 评论(0) 推荐(0)
Pickling
摘要：Pickle translates almost any type of object into a string. pickle.dumps takes an object as a parameter and returns a string representation. ... 阅读全文
posted @ 2014-09-23 22:10 平静缓和用胸音说爱 阅读(200) 评论(0) 推荐(0)
Filenames and paths
摘要：Files are organized into directories (also called ‘folders’). Every running program has a ‘current directory’, which is the default directory for most... 阅读全文
posted @ 2014-09-23 15:27 平静缓和用胸音说爱 阅读(214) 评论(0) 推荐(0)
Format operator
摘要：The argument of write has to be a string, so if we want to put other values in a file, we have to convert them to strings. The easiest way to do that ... 阅读全文
posted @ 2014-09-23 11:55 平静缓和用胸音说爱 阅读(214) 评论(0) 推荐(0)
Reading and writing
摘要：A text file is a sequence of characters stored on a permanent medium like a hard drive, flash memory, or CD-ROM. To read a file, you can use open to c... 阅读全文
posted @ 2014-09-22 23:30 平静缓和用胸音说爱 阅读(234) 评论(0) 推荐(0)
Persistence
摘要：Most of the programs we have seen so far are transient in the sense that they run for a short time and produce some output, but when they end, their d... 阅读全文
posted @ 2014-09-22 22:31 平静缓和用胸音说爱 阅读(277) 评论(0) 推荐(0)
Random words
摘要：To choose a random word from the histogram, the simplest algorithm is to build a list with multiple copies of each word, according to the observed fre... 阅读全文
posted @ 2014-08-17 18:22 平静缓和用胸音说爱 阅读(311) 评论(0) 推荐(0)
Dictionary subtraction
摘要：Finding the words from the book that are not in the word list from words.txt is a problem you might recognize as set subtraction; that is, we want to ... 阅读全文
posted @ 2014-08-17 16:54 平静缓和用胸音说爱 阅读(186) 评论(0) 推荐(0)
Optional arguments
摘要：We have seen built-in functions that take a variable number of arguments. For example range can take one, two or three arguments.It is possible to wri... 阅读全文
posted @ 2014-08-17 16:32 平静缓和用胸音说爱 阅读(331) 评论(0) 推荐(0)
Most common words
摘要：To find the most common words, we can apply the DSU pattern; most_common takes a histogram and returns a list of word-frequency tuples, sorted in reve... 阅读全文
posted @ 2014-08-17 16:16 平静缓和用胸音说爱 阅读(217) 评论(0) 推荐(0)
Word histogram
摘要：Here is a program that reads a file and builds a histogram of the words in the file: process_file loops through the lines of the file, passi... 阅读全文
posted @ 2014-08-17 15:09 平静缓和用胸音说爱 阅读(231) 评论(0) 推荐(0)
Random numbers
摘要：Most computer programs do the same thing every time they execute, given the same inputs, so they are said to be deterministic. Deterministic is usuall... 阅读全文
posted @ 2014-08-14 16:28 平静缓和用胸音说爱 阅读(280) 评论(0) 推荐(0)
Word frequency analysis
摘要：Write a program that reads a file, breaks each line into words, scripts whitespace and punctuation from the words, and converts them to lowercase. Mod... 阅读全文
posted @ 2014-08-10 21:38 平静缓和用胸音说爱 阅读(334) 评论(0) 推荐(0)
DSU
摘要：DSU stands for ‘decorate, sort, undecorate’ and refers to a pattern that is often useful for sorting lists according to some attribute of elements.For... 阅读全文
posted @ 2014-08-10 15:19 平静缓和用胸音说爱 阅读(235) 评论(0) 推荐(0)
Sequences of sequences
摘要：I have focused on lists of tuples, but almost all the examples in this chapter also work with lists of lists, tuples of tuples, and tuples of lists. T... 阅读全文
posted @ 2014-07-24 20:30 平静缓和用胸音说爱 阅读(257) 评论(0) 推荐(0)
Dictionaries and tuples
摘要：Dictionaries have a method called items that returns a list of tuples, where each tuple is a key-value pair. As you should expect from a dictionary, t... 阅读全文
posted @ 2014-07-19 20:22 平静缓和用胸音说爱 阅读(196) 评论(0) 推荐(0)
Lists and tuples
摘要：zip is a built-in function that takes two or more sequence and ‘zips’ them into a list of tuples, where each tuple contains one element from each sequ... 阅读全文
posted @ 2014-07-19 17:25 平静缓和用胸音说爱 阅读(269) 评论(0) 推荐(0)
Tuples as return values
摘要：Strictly speaking, a function can only return one value, but if the value is a tuple, the effect is the same as returning multiple values. For example... 阅读全文
posted @ 2014-07-19 15:14 平静缓和用胸音说爱 阅读(286) 评论(0) 推荐(0)
Tuple assignment
摘要：It is often useful to swap the values of two variables. With conventional assignments, you have to use a temporary variable. This solution is cumberso... 阅读全文
posted @ 2014-07-19 15:04 平静缓和用胸音说爱 阅读(286) 评论(0) 推荐(0)
Tuples are immutable
摘要：A tuple is a sequence of values. The values can be any type, and they are indexed by integers, so in that respect tuples are a lot like lists. The imp... 阅读全文
posted @ 2014-07-15 19:59 平静缓和用胸音说爱 阅读(206) 评论(0) 推荐(0)

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