代表参数的Python动态字符串[i]

Question

I have a problem with Python and I tried searching for an answer here on SO but I can't seem to interpret any of the solutions supplied so far. I supply my python program with command line arguments (sys.argv) and the number of these argument may change from one run to another so I decided that it would be best to make an for loop that creates a new variable for each argument. The first argument is as we all know the script name, I dont want to include this, the second argument is a password string and i dont want this either, so it starts from the third argument. The print at the end is just to see if it works or not.

TempPersonNr = len(sys.argv)
TempPersonNr -= 2
VarPersonNr = ""

i = 1
for TempPersonNr in sys.argv[2:]:
  VarPersonNr[i] = sys.argv[i]
  print (VarPersonNr[i])
  i += 1

Error:

Traceback (most recent call last):
  File "HIDDEN", line 31, in <module>
    VarPersonNr[i] = sys.argv[i]
TypeError: 'str' object does not support item assignment

I want the output to be something like this.

Argument 1 = A
Argument 2 = B
Argument 3 = C

If i supply the program with the following command line arguments I want it to create 3 variables with the value as the argument. For example.

VarPersonNr1  (with the value of argument 1) 
VarPersonNr2  (with the value of argument 2) 
VarPersonNr3  (with the value of argument 3) 

Answer 1

String objects are immutable you can't change it. So when you are trying to assign the i th variable of the string to sys.argv[i] it gives an error.

EDIT: As per your input and output you can directly assign the third value of sys.argv to your variable. varPersonNr3=sys.argv[i]

If you want to add rest of the arguments to that variable use: VarPersonNr3.append(sys.argv[i])

EDIT: There are a couple of options for this: 1) You can use a dictionary to store the variable names as key and the sys.argv value as values:

d={}
TempPersonNr = len(sys.argv)
TempPersonNr -= 2
VarPersonNr = ""

i = 1
for TempPersonNr in sys.argv[2:]:
  key="VarPersonNr"+str(i)
  d[key]=sys.argv[i]
  i += 1

This will give you a dictionary {"VarPersonNr3":'C',"VarPersonNr4":'D'} and so on 2) You can add all the values to a list and fetch it from there. 3) This is a very bad option and should not be used .. but still:

import sys
this = sys.modules[__name__]
i=1
for TempPersonNr in sys.argv[2:]:
   setattr(this, 'VarPersonNr%s' % i, sys.argv[i])
   i+=1
print(VarPersonNr3)
#this will give you the third value

Try using a dict or a list for this.

Answer 2

Try this, so you'll have a list (you can name new variables in the way you described). Also i think you don't get well how for loops work...

TempPersonNr = len(sys.argv) - 2
VarPersonNr = []

for TempPerson in sys.argv[2:]:
    VarPersonNr.append(TempPerson)
    print (TempPerson)