How to create a dictionary and a dataframe in Python through loops

Question

For example, if

list1=[1,2,3]
list2=[[1,1,1],[2,2,2],[3,3,3]]

I'd like to create a dictionary like

dict1={'1':[1,1,1],'2':[2,2,2],'3':[3,3,3]}

How can I realize it through loops? I tried

dict1=dict().fromkeys(list1)
for i in range(len(list1)):
    dict1['i']=list2[i]

But I failed, so is there anyone can help me deal with this problem? One more question, if I firstly create an empty dataframe, df1

df1=pd.DataFrame()

and I hope use the elements in list1 as columns' name of df1. How can I realize it?

Thanks for your assistance!

dict(zip(map(str, list1),list2))

Julien
– Julien

2016-12-09 02:28:08 +00:00
Commented Dec 9, 2016 at 2:28 — Julien
– Julien, Commented Dec 9, 2016 at 2:28

akuiper · Accepted Answer · 2016-12-09 02:35:28Z

1

You can use zip() with dict() to convert the two lists to a dictionary:

dict(zip(list1, list2))
# {1: [1, 1, 1], 2: [2, 2, 2], 3: [3, 3, 3]}

To construct a data frame with list1 as columns:

pd.DataFrame(dict(zip(list1, list2)))

#   1   2   3
#0  1   2   3
#1  1   2   3
#2  1   2   3

edited Dec 9, 2016 at 2:35

answered Dec 9, 2016 at 2:28

akuiper

216k33 gold badges363 silver badges380 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Chinny84 · Accepted Answer · 2016-12-09 02:29:18Z

0

You failed if you tried to use

dict1['i']

instead of

dict1[i]

Since you are only using the letter/string i as the key whilst you have keys generated from the list i.e. ['1','2','3']

If you are starting off you should look at coding it up like this then move to move pythonic ways.

dict1 = {}
for i, key in enumerate(map(str,list1)):
     if key not in dict1:
          dict1[key] = list2[i]

This will get you thinking about dictionaries.

answered Dec 9, 2016 at 2:29

Chinny84

9667 silver badges17 bronze badges

Comments

Mr.Roboto · Accepted Answer · 2016-12-09 02:29:28Z

0

You can just append the items into the dictionary if you want to use loops.

d = {}
l = [1,2,3,4,5]
for i in range(len(l)): 
    d[i] = l[i]

When you print d you will have {0: 1, 1: 2, 2: 3, 3: 4, 4: 5}

answered Dec 9, 2016 at 2:29

Mr.Roboto

1913 silver badges14 bronze badges

Collectives™ on Stack Overflow

How to create a dictionary and a dataframe in Python through loops

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related