如何计算代码中关键字的出现次数但忽略注释/文档字符串中的关键字？

Question

我是 Python 的新手。我想在下面的代码中找到 Python 关键字 ['def','in', 'if'...] 的出现。但是，需要忽略代码中任何字符串常量中的关键字。如何在不计算字符串中出现的关键字的情况下计算关键字的出现次数？

def grade(result):
    '''
    if if (<--- example to test if the word "if" will be ignored in the counts)
    :param result: none
    :return:none
    '''

    if result >= 80:
        grade = "HD"
    elif 70 <= result:
        grade = "DI"
    elif 60 <= result:
        grade = "CR"
    elif 50 <= result:
        grade = "PA"
    else:
    #else (ignore this word)
        grade = "NN"
    return grade

result = float(raw_input("Enter a final result: "))

while result < 0 or result > 100:
    print "Invalid result. Result must be between 0 and 100."
    result = float(raw_input("Re-enter final result: "))

print "The corresponding grade is", grade(result)

Answer 1

使用 tokenize、keyword 和 collections 模块。

tokenize.generate_tokens(readline)

The generate_tokens() generator requires one argument, readline, which must be a callable object which provides the same interface as the readline() method of built-in file objects (see section File Objects). Each call to the function should return one line of input as a string. Alternately, readline may be a callable object that signals completion by raising StopIteration.

The generator produces 5-tuples with these members: the token type; the token string; a 2-tuple (srow, scol) of ints specifying the row and column where the token begins in the source; a 2-tuple (erow, ecol) of ints specifying the row and column where the token ends in the source; and the line on which the token was found. The line passed (the last tuple item) is the logical line; continuation lines are included.

New in version 2.2.

import tokenize
with open('source.py') as f:
    print list(tokenize.generate_tokens(f.readline))

部分输出：

[(1, 'def', (1, 0), (1, 3), 'def grade(result):\n'),
 (1, 'grade', (1, 4), (1, 9), 'def grade(result):\n'),
 (51, '(', (1, 9), (1, 10), 'def grade(result):\n'),
 (1, 'result', (1, 10), (1, 16), 'def grade(result):\n'),
 (51, ')', (1, 16), (1, 17), 'def grade(result):\n'),
 (51, ':', (1, 17), (1, 18), 'def grade(result):\n'),
 (4, '\n', (1, 18), (1, 19), 'def grade(result):\n'),
 (5, '    ', (2, 0), (2, 4), "    '''\n"),
 (3,
  '\'\'\'\n    if if (<--- example to test if the word "if" will be ignored in the counts)\n    :param result: none\n    :return:none\n    \'\'\'',
  (2, 4),
  (6, 7),
  '    \'\'\'\n    if if (<--- example to test if the word "if" will be ignored in the counts)\n    :param result: none\n    :return:none\n    \'\'\'\n'),
 (4, '\n', (6, 7), (6, 8), "    '''\n"),
 (54, '\n', (7, 0), (7, 1), '\n'),
 (1, 'if', (8, 4), (8, 6), '    if result >= 80:\n'),

您可以从 keyword 模块中检索关键字列表：

import keyword
print keyword.kwlist
print keyword.iskeyword('def')

与collections.Counter的集成解决方案：

import tokenize
import keyword
import collections 
with open('source.py') as f:
    # tokens is lazy generator
    tokens = (token for _, token, _, _, _ in tokenize.generate_tokens(f.readline))
    c = collections.Counter(token for token in tokens if keyword.iskeyword(token))

print c  # Counter({'elif': 3, 'print': 2, 'return': 1, 'else': 1, 'while': 1, 'or': 1, 'def': 1, 'if': 1})

如何计算代码中关键字的出现次数但忽略注释/文档字符串中的关键字？

How to count the occurrences of keywords in code but ignore the ones in comment / docstring?

python

file

count

keyword

python-2.7