PyParsing:这是setParseAction()的正确使用吗? [英] PyParsing: Is this correct use of setParseAction()?

问题描述

我有这样的字符串:

"MSE 2110, 3030, 4102"

我想输出:

[("MSE", 2110), ("MSE", 3030), ("MSE", 4102)]

这是我的解决方法，尽管我还没有得到:

This is my way of going about it, although I haven't quite gotten it yet:

def makeCourseList(str, location, tokens):
    print "before: %s" % tokens

    for index, course_number in enumerate(tokens[1:]):
        tokens[index + 1] = (tokens[0][0], course_number)

    print "after: %s" % tokens

course = Group(DEPT_CODE + COURSE_NUMBER) # .setResultsName("Course")

course_data = (course + ZeroOrMore(Suppress(',') + COURSE_NUMBER)).setParseAction(makeCourseList)

这将输出:

>>> course.parseString("CS 2110")
([(['CS', 2110], {})], {})
>>> course_data.parseString("CS 2110, 4301, 2123, 1110")
before: [['CS', 2110], 4301, 2123, 1110]
after: [['CS', 2110], ('CS', 4301), ('CS', 2123), ('CS', 1110)]
([(['CS', 2110], {}), ('CS', 4301), ('CS', 2123), ('CS', 1110)], {})

这是正确的方法吗?还是我完全不满意?

Is this the right way to do it, or am I totally off?

另外，的输出不是很正确-我希望course_data发出一个course符号的列表，这些符号彼此的格式相同.目前，第一门课程不同于其他课程. (它有一个{}，而其他没有.)

Also, the output of isn't quite correct - I want course_data to emit a list of course symbols that are in the same format as each other. Right now, the first course is different from the others. (It has a {}, whereas the others don't.)

推荐答案

此解决方案在解析时会记住部门，并在找到数字时发出(dept，coursenum)元组.

This solution memorizes the department when parsed, and emits a (dept,coursenum) tuple when a number is found.

from pyparsing import Suppress,Word,ZeroOrMore,alphas,nums,delimitedList

data = '''\
MSE 2110, 3030, 4102
CSE 1000, 2000, 3000
'''

def memorize(t):
    memorize.dept = t[0]

def token(t):
    return (memorize.dept,int(t[0]))

course = Suppress(Word(alphas).setParseAction(memorize))
number = Word(nums).setParseAction(token)
line = course + delimitedList(number)
lines = ZeroOrMore(line)

print lines.parseString(data)

输出:

[('MSE', 2110), ('MSE', 3030), ('MSE', 4102), ('CSE', 1000), ('CSE', 2000), ('CSE', 3000)]

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