python concatenating a list without restarting-CodePudding

I'm trying to concatenate new rows of data into an old main dataframe. However, whenever I try to run my for loop. My old main dataframe restarts that's because of the exfive = pd.DataFrame() however without it. The Dataframe wouldn't have even been created. Also, if I hash it. The output gives me double the concatenated rows. So how do I go about being able to concatenate new rows of data without restarting or doubling my main?

nums_list = [2000,5500]
nums_list_two = [8000, 9000]

for num_list, num_list_two in zip(nums_list, nums_list_two):
    ex5 = pd.DataFrame({'colone':nums_list,'coltwo':nums_list_two})
    ex6 = pd.DataFrame({'colones':nums_list_two,'coltwos':nums_list})
    exs_list = [ex5, ex6]
        
    ex_mod = []
    for ex_list in exs_list:
        ex_list = ex_list.T
        ex_mod.append(ex_list)
            
    ex5 = ex_mod[0]
    ex6 = ex_mod[1]
    exfive = pd.DataFrame()
    exfive = pd.concat([exfive, ex5], ignore_index = False, axis = 0)
    del ex5

desired output:

          0      1
colone  1000    4500
coltwo  7000    8000
colone  2000    5500
coltwo  6000    9000

What I get when I have the pd.Dataframe not hashed:

          0      1
colone  2000    5500
coltwo  6000    9000

What I get when I have the pd.Dataframe hashed:

          0      1
colone  1000    4500
coltwo  7000    8000
colone  2000    5500
coltwo  6000    9000
colone  2000    5500
coltwo  6000    9000

I've tried this:

nums_list = [2000,5500]
nums_list_two = [8000, 9000]
exfive = pd.DataFrame()

for num_list, num_list_two in zip(nums_list, nums_list_two):
    ex5 = pd.DataFrame({'colone':nums_list,'coltwo':nums_list_two})
    ex6 = pd.DataFrame({'colones':nums_list_two,'coltwos':nums_list})
    exs_list = [ex5, ex6]

    ex_mod = []
    for ex_list in exs_list:
        ex_list = ex_list.T
        ex_mod.append(ex_list)

    ex5 = ex_mod[0]
    ex6 = ex_mod[1]
    exfive = exfive.append(ex5)

I don't get the desired outcome:

          0       1
colone  1000    4500
coltwo  7000    8000
colone  1000    4500
coltwo  7000    8000

I've also put the concat outside the for loop below it.

finalexfive = pd.concat(exfive, ignore_index = False, axis = 0)

But I get the outcome:

TypeError: first argument must be an iterable of pandas objects, you passed an object of type "DataFrame"

CodePudding user response：

Simple answer

Say you have df1 and you create df2 with the new list, provided they have the same column names, try doing df = pd.DataFrame(df1, df2)

Do tell if this worked.

CodePudding user response：

Try doing this

df = pd.DataFrame([[1, 2], [3, 4]], columns = ["a", "b"])
print(df)
to_append = [5, 6]
a_series = pd.Series(to_append, index = df.columns)
df = df.append(a_series, ignore_index=True)

This might also work. Basically you are trying to add new rows to the existing dataframe.