about streamtoken

[Lin Armis]

hi all:
In java,there is streamtoken method to deal with input string.
how does the python do this work?
Supposed that input "aa/dd/as/23/a22",I wanna the string "23" change to
int('23'),but how can I tell the diffrent between '23'and 'aa' in the all
strings?in java ,I can use streamtoken to recognize the number type and
string type from input,but i dont know how is in Python.

cheers,

Mian

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[Peter Otten]

hi all:
In java,there is streamtoken method to deal with input string.
how does the python do this work?
Supposed that input "aa/dd/as/23/a22",I wanna the string "23" change to
int('23'),but how can I tell the diffrent between '23'and 'aa' in the all
strings?in java ,I can use streamtoken to recognize the number type and
string type from input,but i dont know how is in Python.

Here is one simplistic way to do it:

s = "aa/dd/as/23/a22"
def convert(s, converters=[int, float]):

.... for c in converters:
.... try:
.... return c(s)
.... except ValueError:
.... pass
.... return s
....

a = [convert(t) for t in s.split("/")]
a

['aa', 'dd', 'as', 23, 'a22']

Use introspection to detect a token's type:

isinstance(a[0], int) False
isinstance(a[3], int)

True

For more complicated input you could use regular expressions.

Peter