Dynamically accessing variables in python

Question

There are 9 texts called text1, text2, ... text9. A function is defined as follow.

def lexical_diversity(text):
 return len(set(text))/len(text)

I want to call the function for all 9 texts with following code. But the outpu is wrong.

for i in range(1,10):
 a='text'+str(i)
 print(lexical_diversity(a))

My output is

0.8
0.8
...
0.8

If applying the function to text1, I get following result.

>>>lexical_diversity(text1)
 Out[37]:0.07406285585022564

So which part goes wrong?

• coldspeed95: What does text1 contain?
• spectras: 'text'+str(i)gives "text1", "text2", ... the actual strings. So you get the lexical diversity of "text1", "text2", ... If you have multiple texts you want to access, you probably want to store them in an array, not in separated variables otherwise you cannot loop on them.
• Lei Hao: @spectras I see my errors. Thanks. Anyway to fix it?
• spectras: @LeiHao> well, I didn't add anything because cᴏʟᴅsᴘᴇᴇᴅ's answer below is the right way to do this. I would suggest you look for python list tutorial on your search engine of choice, you'll get a better understanding of how to handle lists of things :)

Answer 1

You should understand that a = 'text' + str(i) does not magically bestow upon a the value of whatever is contained inside the variable text1. Instead, a is assigned to the string "text1". The two are not the same.

Given the names, you should probably consider storing your texts in a list:

texts = [text1, text2, text3, ...]

And now,

for a in texts:
 print(lexical_diversity(a))

• spectras: Given the names I would advocate an array. texts[i] sounds better than texts["text"+str(i)].
• spectras: What I mean is given his variable names, I believe there is no semantic content in his text1, text2, .... He merely have texts, and added a number to his variables names.
• Lei Hao: I see my errors. Is there a way to create this list quickly, instead of typing text1, text2,...? A for-loop or something?
• coldspeed95: @LeiHao Yes. There's a quick and dirty solution. It involves manipulating globals. Do this: texts = [globals()['text' + str(i)] for i in range(1, 10)] You must wonder... why not use globals directly? Well, it's major code smell.
• coldspeed95: @akp That just puts strings in there, not the actual variable content.

Answer 2

Python3

def lexical_diversity(text):
 return len(set(text))/len(text)
lista = []
for i in range(1,10):
 lista.append("text%d" % i) 
for resVal in lista:
 print(resVal) 
 print(lexical_diversity(resVal))