How to include a variable name inside a variable name?

Question

Here is what I have:

names1 = ['bob', 'jack', 'adam', 'dom' ]


num = int(input('Please select a number? ')) # select number 1

for name in names + num: # This is where my problem is
    print (s)

I want the names + num part to refer to the names1 list. How would you do that?

Any help would be much appreciated!

"How would you do that?" Answer: We would not do that. AFK now, but I'm sure someone will explain it in short time. — Matthias, Jun 03 '15 at 14:01
This question is nonsense without a second list. The comment `#select number 1` is... ...what you are hoping? — Wolf, Jun 03 '15 at 14:37
This was marked as duplicate of an existing question. However, it should be noted that what you're asking how to do is not a good way to solve your problem, and some of the answers already given suggest some better ways to think about it using the right *data structures*. Happy hacking! — Iguananaut, Jun 03 '15 at 14:38

ZdaR · Answer 1 · 2015-06-03T14:10:19.223

There are two options, either you can use, nested list structure or a dictionary.

Nested list:

parent_list = [['bob', 'jack', 'adam', 'dom'], ["alpha", "beta", "gamma"], ["India", "USA"]]
num = int(input('Please select a number? '))
#Checking if the value entered can be accessed or not.
if num<3:
    for name in parent_list[num]:
        print name
else:
    print "Please enter a number between 0-2"

Dictionaries:

parent_dict = {0:['bob', 'jack', 'adam', 'dom'], 1:["alpha", "beta", "gamma"], 2:["India", "USA"]}
num = int(input('Please select a number? '))

if num<3:
    for name in parent_dict[num]:
        print name
else:
    print "Please enter a number between 0-2"

If you already have variables created in your script then you may choose to create a dictionary or nested list of variables:

names1 = ['bob', 'jack', 'adam', 'dom' ]
names2 = ["alpha", "beta", "gamma"]
names3 = ["India", "USA"]

#For nested list part
parent_list = [names1, names2, names3]

#For dictionary part
parent_dict = {0:names1, 1:names2, 2:nmaes3}

score 1 · Answer 2 · edited May 23 '17 at 12:21

The correct way to do this is to use either a list or dict data structure to store a set of choices, then write a simple function that prompts the user for input and validates it against "valid choices".

Example:

from __future__ import print_function

try:
    input = raw_input
except NameError:
    input = raw_input  # Python 2/3 compatibility

names = ["bob", "jack", "adam", "dom"]

def prompt(prompt, *valid):
    try:
        s = input(prompt).strip()
        while s not in valid:
            s = input(prompt).strip()
        return s
    except (KeyboardInterrupt, EOFError):
        return ""

choices = list(enumerate(names))
print("Choices are: {0}".format(", ".join("{0}:{1}".format(i, name) for i, name in choices)))

try:
    s = prompt("Your selection? ", *(str(i) for i, _ in choices))
    i = int(s)
except ValueError:
    print("Invalid input: {0}".format(s))
else:
    print("Thanks! You selected {0}".format(choices[i][1]))

Demo:

$ python foo.py
Choices are: 0:bob, 1:jack, 2:adam, 3:dom
Your selection? 0
Thanks! You selected bob

$ python foo.py
Choices are: 0:bob, 1:jack, 2:adam, 3:dom
Your selection? foo
Your selection? 1
Thanks! You selected jack

This also correctly handles the scenario of invalid inputs and int() throwing a ValueError as well as silencing ^D (EOFError) and ^C (KeyboardInterrupt) exceptions.

Note: That you could do for name in eval("names{0:d}".format(num)): however DO NOT do this as it's considered evil and quite dangerous to arbitrarily evaluate input using eval(). SeE: Is using eval() in Python bad pracice?

score 0 · Answer 3 · answered Jun 03 '15 at 14:35

names1 = ['bob', 'jack', 'adam', 'dom' ]

num = int(input('Please select a number? ')) # select number 1
name_array = "names" + str(num)
for name in name_array: # This is where my problem is
    print(name)

Here we have just concatenated the name_array value. Hope it works for you too.

score -2 · Answer 4 · answered Jun 03 '15 at 14:07

-2

Use This Source

names1 = ['bob', 'jack', 'adam', 'dom' ]


num = int(input('Please select a number? ')) # select number 1
for counter in range (num,4):
   print(names1[counter]);

answered Jun 03 '15 at 14:07

iman mir

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This doesn't answer the question asked. – ZdaR Jun 03 '15 at 14:14

How to include a variable name inside a variable name?

4 Answers4