计算字符串中的单词数

Question

what I'm doing right now is counting the number of spaces, then add 1
but what if the user enters something like "heres a big space______amazing right?"
the program would count all those 6 spaces and say, there are 10 words when actually it is 6

phrase = raw_input("Enter a phrase: ")
space_total = 0
for ch in phrase:
    if ch == " ":
        space_total += 1
words = space_total + 1
print "there are", words, "in the sentence"

Answer 1

Use str.split() to split a line on whitespace, then use the length of the result:

len(phrase.split())

str.split() with no arguments, or None as the first argument, will split on arbitrary width whitespace; no matter how many spaces or tabs or newlines are used between words, it'll split to produce just a list of words (where a word is anything that is not whitespace):

>>> 'Hello world!  This\tis\t         awesome!'.split()
['Hello', 'world!', 'This', 'is', 'awesome!']
>>> len('Hello world!  This\tis\t         awesome!'.split())
5

Answer 2

>>> import re
>>> s = "test  test1    test2    abc"
>>> re.findall("\w+", s)
['test', 'test1', 'test2', 'abc']
>>> ret = re.findall("\w+", s)
>>> len(ret)
4