用Python正确的方式解析字符串

Question

I have some problems with parsing the correct way. I want to split the complete string in two seperate strings. And then remove the "="-signs frome the first string and the ","-sign from the 2nd string. From my output I can conclude that I did something wrong, but I do not seem to get where the problem lies. I want the first part to convert to integers, and I've already tried it with map(int, split()).

If anyone has a tip, I would appreciate that.

This is my output:

('5=20=22=10=2=0=0=1=0=1', 'Vincent Appel,Johannes Mondriaan')

This is my program:

mystring = "5=20=22=10=2=0=0=1=0=1;Vincent Appel,Johannes Mondriaan"

def split_string(mystring):
    strings = mystring.split(";")
    x = strings[0]
    y = strings[-1]
    print(x,y)

def split_scores(x):
    scores = x.split("=")
    score = scores[0]
    names = scores[-1]
    stnames(names)
    print score

def stnames(y):
    studentname = y.split(",")
    name = studentname[1]
    print name

split_string(mystring)

Answer 1

split_string(mystring) runs the 1st function, producing the tuple with 2 strings. But nothing runs the other functions which are intended to perform further splitting.

try:

x, y = split_string(mystring)
x1 = split_scores(x)
y1 = stnames(y)
(x1, y1)

oops, your functions print the results, don't return them. So you also need:

def split_string(mystring):
    # split mystring on ";"
    strings = mystring.split(";")
    return strings[0],strings[1]

def split_string(mystring):
    # this version raises an error if mystring does not have 2 parts
    x, y = mystring.split(";")
    return x,y

def split_scores(x):
    # return a list with all the scores
    return x.split("=")

def stnames(y):
    # return a list with all names
    return y.split(",")

def lastname(y):
    # return the last name (, delimited string)
    return y.split(",")[-1]

If you are going to split the task among functions, it is better to have them return the results rather than print them. That way they can be used in various combinations. print within a function only for debugging purposes.

Or a compact, script version:

x, y = mystring.split(';')
x = x.split('=')
y = y.split(',')[-1]
print y, x

If you want the scores as numbers, add:

x = [int(x) for x in x]

to the processing.

Answer 2

Try this:

def split_string(mystring):
    strings = mystring.split(";")
    x = int(strings[0].replace("=",""))
    y = strings[-1].replace(","," ")
    print x,y

Answer 3

My two cents.

If I understood what you want to achieve, this code could help:

mystring = "5=20=22=10=2=0=0=1=0=1;Vincent Appel,Johannes Mondriaan"

def assignGradesToStudents(grades_and_indexes, students):
    list_length = len(grades_and_indexes)
    if list_length%2 == 0:
        grades = grades_and_indexes[:list_length/2]
        indexes = grades_and_indexes[list_length/2:]
        return zip([students[int(x)] for x in indexes], grades)

grades_and_indexes, students = mystring.split(';')
students = students.split(',')
grades_and_indexes = grades_and_indexes.split('=')

results = assignGradesToStudents(grades_and_indexes, students)
for result in results:
    print "[*] {} got a {}".format(result[0], result[1])

Output:

[*] Vincent Appel got a 5
[*] Vincent Appel got a 20
[*] Johannes Mondriaan got a 22
[*] Vincent Appel got a 10
[*] Johannes Mondriaan got a 2