Parse string into different types

Question

I have looked at this solution but my requirements are slightly different.

I have a string of the form: "command int1 int2", e.g. "download 600 10".

I know I could use str.split(" ") to break the string into its component parts but then I would have to convert the 2nd and 3rd parameters to ints. Thus the following won't work (the int cast fails when it encounters "download" in the string):

(cmd, int1, int2) = [int(s) for s in file.split(' ')]

I'm still pretty new to Python... so I'm wondering if there is a nice, pythonic way to accomplish my goal?

score 5 · Accepted Answer · answered May 14 '17 at 14:06

5

You could maps types to values:

>>> types = (str, int, int)
>>> string = 'download 600 10'
>>> cmd, int1, int2 = [type(value) for type, value in zip(types, string.split())]

>>> cmd, int1, int2
('download', 600, 10)

answered May 14 '17 at 14:06

Peter Wood

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No problem, enjoy. – Peter Wood May 14 '17 at 14:09
`def strToTypes(string, types_tuple): array = [type(value) for type, value in zip(types_tuple, string.split())] return array noun, n1, n2 = strToTypes("noun 3 4", (str, int, float)) print(noun, n1, n2)` – RobertJoseph May 14 '17 at 14:23

score 1 · Answer 2 · answered May 14 '17 at 13:50

1

It depends on your take on what "pythonic" means to you, but here's another way:

words = file.split(" ")
cmd, (int1, int2) = words[0], map(int, words[1:])

answered May 14 '17 at 13:50

jdehesa

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score 1 · Answer 3 · answered May 14 '17 at 13:52

There isn't anything more Pythonic in the standard library. I suggest you just do something simple such as:

cmd = file.split(' ')
command = cmd[0]
arg1 = int(cmd[1])
arg2 = int(cmd[2])

You could always try to look for a little parser, but that would be overkill.

score 1 · Answer 4 · edited May 23 '17 at 12:18

From here I have imported the following function, which use isdigit() (see here):

def check_int(s): # check if s is a positive or negative integer
    if s[0] in ('-', '+'):
        return s[1:].isdigit()
    return s.isdigit()

Then you need only this code:

your_string = "download 600 10" 
elements = your_string.split(" ")
goal = [int(x) for x in elements if check_int(x)]

cmd, (int1,int2) = elements[0], goal

score 0 · Answer 5 · answered May 14 '17 at 14:06

0

You can do it like this.

file = "downlaod 600 10"
file_list = file.split(' ')
for i in range(len(file_list)):
 try:
   file_list[i] = int(file_list[i])
 except ValueError:
    pass    
(cmd, int1, int2) = file_list

answered May 14 '17 at 14:06

Abdullah Danyal

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Parse string into different types

5 Answers5