added 0004

robot527/0004/example.txt

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+WHAT IS LINUX?
+
+  Linux is a clone of the operating system Unix, written from scratch by
+  Linus Torvalds with assistance from a loosely-knit team of hackers across
+  the Net. It aims towards POSIX and Single UNIX Specification compliance.
+
+  It has all the features you would expect in a modern fully-fledged Unix,
+  including true multitasking, virtual memory, shared libraries, demand
+  loading, shared copy-on-write executables, proper memory management,
+  and multistack networking including IPv4 and IPv6.
+
+  It is distributed under the GNU General Public License - see the
+  accompanying COPYING file for more details. 
+
+ON WHAT HARDWARE DOES IT RUN?
+
+  Although originally developed first for 32-bit x86-based PCs (386 or higher),
+  today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
+  UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
+  IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
+  Xtensa, Tilera TILE, AVR32 and Renesas M32R architectures.
+
+  Linux is easily portable to most general-purpose 32- or 64-bit architectures
+  as long as they have a paged memory management unit (PMMU) and a port of the
+  GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
+  also been ported to a number of architectures without a PMMU, although
+  functionality is then obviously somewhat limited.
+  Linux has also been ported to itself. You can now run the kernel as a
+  userspace application - this is called UserMode Linux (UML).

robot527/0004/statistic_words.py

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+#! usr/bin/python3
+"""
+第 0004 题：任一个英文的纯文本文件，统计其中的单词出现的个数。
+"""
+
+print('Please input a text file name which in the current working directory.')
+print('Usage - example.txt')
+file_name = input("@> ")
+
+def deal_punctuation(the_string):
+    from string import punctuation as punc
+    punc_list = list(punc)
+    punc_list.remove('-')
+    ret_string = the_string
+    for each_punc in punc_list:
+        ret_string = ret_string.replace(each_punc, ' ')
+    ret_string = ret_string.replace(' -', ' ').replace('- ', ' ')
+    return ret_string
+
+def stat(the_file):
+    try:
+        with open(the_file) as textfile:
+            word_list = []
+            for each_line in textfile:
+                temp = deal_punctuation(each_line)
+                word_list += temp.split()
+            print('This file has ', word_list.__len__(), ' words.')
+            word_set_list = sorted(set(word_list))
+            for each_word in word_set_list:
+                print(each_word + ' : ', word_list.count(each_word))
+    except IOError as err:
+        print('File error: ' + str(err))
+
+if __name__ == '__main__':
+    stat(file_name)