将整个列表转换为字符串

Question

import pandas as pd

raw_data = {'a': ['a'],'b':['b'],'c':['c'],'d':[['a','b']]}
df = pd.DataFrame(raw_data, columns = ['a','b','c','d'])

this results,

    a   b     c        d
0   a   b    c       [a, b]

then i'm adding it into a single column like this df['test'] = df['a']+'+'+df['b']+'+'+df['c']

df['test'] gives a+b+c

After that I'm fetching each single value using this

finalArr = df['test'][0]
finalArr = finalArr.split("+")
one = finalArr[0]
two = finalArr[1]
three = finalArr[2]

How to add df['d'] to this:

df['test'] = df['a']+'+'+df['b']+'+'+df['c']

and fetch four = finalArr[3]

expected output:

df['test'] 

a+b+c+[a,b]


four = finalArr[3]
[a,b]


[a,b] should be in list format while fetching

Answer 1

Use, Dataframe.agg on axis 1 to join the columns a, b, c around seperator + then use Series.str.join to join the list then concatenate it with square brackets:

df['test'] =  df[['a', 'b', 'c']].agg('+'.join, axis=1) + '+[' + df['d'].str.join(',') + ']'

---

# print(df)
   a  b  c       d         test
0  a  b  c  [a, b]  a+b+c+[a,b]

Answer 2

# Python program to convert a list to string 

# Function to convert 
def listToString(s): 

    # initialize an empty string 
    str1 = "" 

    # traverse in the string 
    for ele in s: 
        str1 += ele 

    # return string 
    return str1 


# Driver code    
s = ['Geeks', 'for', 'Geeks'] 
print(listToString(s)) 

Answer 3

you can simply use this line string=[str(value) for value in df.iloc[0,:]]

 import pandas as pd

 raw_data = {'a': ['a'],'b':['b'],'c':['c'],'d':[['a','b']]}
 df = pd.DataFrame(raw_data, columns = ['a','b','c','d'])

 string=[str(value) for value in df.iloc[0,:]]
 df['test']=pd.Series({0:string})
 print(string[3])

 "['a', 'b']"

Answer 4

Try this out:

s = '[' + df['d'].str.join(', ') + ']' #first convert your list to a string
df['test'][0] += '+' + s               #then add it to your variable

The result will be:

>>>print(df['test'][0])
"a+b+c+[a, b]"

And then if you want to fetch it as a list, you can use this:

arr = df['test'][0].split('+')
arr[3] = arr[3][1:-1].split(', ') #convert the string to a list. 
# [1: -1] removes the brackets ('[', ']')
# you can also use .strip('[]') instead

Good luck with your project;)