下面来提取童话 Alicein Wonderland 的文本，并尝试计算它包含多少个单词。我们将使用方法split() ，它根据一个字符串创建一个单词列表。方法split() 以空格为分隔符将字符串分拆成多个部分，并将这些部分都存储到一个列表中。
>>> title = "Alice in Wonderland" >>> title.split() [‘Alice‘, ‘in‘, ‘Wonderland‘]
filename = ‘alice.txt‘ try: with open(filename) as f_obj: contents = f_obj.read() except FileNotFoundError: msg = "Sorry, the file " + filename + " does not exist." print(msg) else: # 计算文件大致包含多少个单词 words = contents.split() num_words = len(words) print("The file " + filename + " has about " + str(num_words) + " words.") #The file alice.txt has about 29461 words.
分析多个文件
def count_words(filename): """计算一个文件大致包含多少个单词""" try: with open(filename) as f_obj: contents = f_obj.read() except FileNotFoundError: msg = "Sorry, the file " + filename + " does not exist." print(msg) else: # 计算文件大致包含多少个单词 words = contents.split() num_words = len(words) print("The file " + filename + " has about " + str(num_words) +" words.") filenames = [‘alice.txt‘, ‘siddhartha.txt‘, ‘moby_dick.txt‘, ‘little_women.txt‘] for filename in filenames: count_words(filename) #循环执行函数 ‘‘‘ The file alice.txt has about 29461 words. Sorry, the file siddhartha.txt does not exist.有一个文件没有 The file moby_dick.txt has about 215136 words. The file little_women.txt has about 189079 words. ‘‘‘
如果缺少一个文件但是不想报错，就像什么都没有发生一样继续运行。个pass语句，可在代码块中使用它来让Python 什么都不要做。
def count_words(filename): """计算一个文件大致包含多少个单词""" try: --snip-- except FileNotFoundError: pass #直接过，什么都不做 else: --snip-- filenames = [‘alice.txt‘, ‘siddhartha.txt‘, ‘moby_dick.txt‘, ‘little_women.txt‘] for filename in filenames: count_words(filename) ‘‘‘ The file alice.txt has about 29461 words. The file moby_dick.txt has about 215136 words. The file little_women.txt has about 189079 words. ‘‘‘