create panda dataframe and append values in for loop

Question

I have a list from which I would like to iterate over and create tuples in a pandas dataframe in order to imitate sliding window of size 4. What I am trying to do is:

tuples = pd.DataFrame()
for index, row in expertsDF.iterrows():
      newlst = row['name'] 
      counter = 0
      for x in newlst:
        if counter < len(newlst) - 3:
            tuples['A'] = x
            tuples['B'] =newlst(counter+1)
            tuples['C'] =newlst(counter+2)
            tuples['D'] =newlst(counter+3)
            counter = counter + 1

the newlst looks like this:

list (var1, var2, var3....)

and my DataFrame should be like this:

     A       B      C       D
1   var1   var2   var3    var4
2   var2   var3   var4    var5
3   var3   var4   var5    var6

Is there a way to do that in python?

the code inside the if condition is not correct, therefore I have no output. I just tried to show what I am trying to do. — Kratos
– Kratos, Commented Oct 4, 2016 at 18:06
it is from library itertools. I used it to iterate through the initial dataframe where my values where stored. — Kratos
– Kratos, Commented Oct 4, 2016 at 18:30

nullop · Accepted Answer · 2016-10-04 20:20:26Z

1

Is this close?

import pandas as pd
tuples = pd.DataFrame(columns=['A', 'B', 'C', 'D'])
newlst = "abcdefg"
i = 0
for x in newlst:
    if i < len(newlst) - 3:
        t = pd.DataFrame([[x, newlst[i + 1], newlst[i + 2], newlst[i + 3]]],
                         columns=['A', 'B', 'C', 'D'])
    tuples = tuples.append(t, ignore_index=True)
    i += 1
print tuples

This prints:

   A  B  C  D
0  a  b  c  d
1  b  c  d  e
2  c  d  e  f
3  d  e  f  g

edited Oct 4, 2016 at 20:20

answered Oct 4, 2016 at 20:13

nullop

5542 silver badges6 bronze badges

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

Comments

akovner · Accepted Answer · 2016-10-04 20:36:02Z

1

How about creating the DataFrame from Series objects?

import pandas as pd

data_list = list(map(lambda x: 'var{}'.format(x),range(0,100)))
df = pd.Series(data_list[0:97]).to_frame(name='A')
df['B'] = pd.Series(data_list[1:98])
df['C'] = pd.Series(data_list[2:99])
df['D'] = pd.Series(data_list[3:100])

df.head()

# output
#       A     B     C     D
# 0  var0  var1  var2  var3
# 1  var1  var2  var3  var4
# 2  var2  var3  var4  var5
# 3  var3  var4  var5  var6
# 4  var4  var5  var6  var7

answered Oct 4, 2016 at 20:36

akovner

1181 silver badge5 bronze badges

Collectives™ on Stack Overflow

create panda dataframe and append values in for loop

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related