CODEWITHSUNDEEP
pythonlistfunctionindexing
fredflintstone2000
fredflintstone2000

Reputation: 13

Defining several variables simultaneously in Python

For each object in my Python list, I want to define an integer which is the first index of the object:

firstindex( some object ) = mylist.index( some object)

How do I make such a definition for all objects simultaneously?

I tried doing this:

firstindex = []
i=1

while i < 100 :
    firstindex.append( mylist.index("i") )
    i=i+1

But it tells me that 'i' is not in the list. However the list is of the form [1,1,1,1,1,1,2,2,2,2,2,3,3,3,3,....]

Upvotes: 0

Views: 63

Answers (3)

Max Sirwa
Max Sirwa

Reputation: 151

Why don't you just use a dictionnary?

d = dict() # or d = {}
for i in range(100):
   d['firstindex_'+str(i)] = ""

This would create a dictionnary of size 100 with all values as empty strings. You can access it with d['firstindex_0'] through d['firstindex_99'].

Upvotes: 1

RoaaGharra
RoaaGharra

Reputation: 710

You should change your code to the following:

firstindex = []
i= 1

while i < 100 :
    firstindex.append( mylist.index(str(i)) )
    i=i+1

Your previous code searched for an item in the list with the value "i" which is the string "i". You instead want to search for the value of the variable i which is the string "1" then "2" then "3" and so on. So you should simply search for the index of str(i).

Str(i) returns a string of the value in i.

Upvotes: 1

developer_hatch
developer_hatch

Reputation: 16224

That's because the funct list.index(obj) return the index of the object in the list.

>>> ["foo", "bar", "baz"].index("bar")
1

And your list "mylist" is a list of object that may not content the index "i", that is a String

Upvotes: 0

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