python pandas to_csv附加模式生成不需要的未知行

Question

using to_csv appending mode generates unwanted unknown rows.

For example:

check = [0,0,0]
df = pd.DataFrame([check])
df.to_csv('test.csv', index=False)
df = pd.DataFrame([check])
df.to_csv('test.csv', mode='a', index=False)
df = pd.read_csv('test.csv')

returns 0 1 2 0 0 0 0 1 0 1 2 2 0 0 0

where the 1 0 1 2 is unwanted and unknown extra row.

What is the problem here?

Answer 1

Found that the extra unwanted row 1 0 1 2 is the columns' name. Then I just tried following

check = [0,0,0]
df = pd.DataFrame([check])
df.to_csv('test.csv', index=False)
df = pd.DataFrame([check])
df.to_csv('test.csv', mode='a', index=False, header=False)
df = pd.read_csv('test.csv')

returns

    0   1   2
0   0   0   0
1   0   0   0

with header=False to ignore the header/columns'name, then it returns what I want.