to_csv has changed the number

[honghong2333]

Code Sample, a copy-pastable example if possible

df1 = pd.read_csv("./data/test.csv")
print(df1)
df1.to_csv("./data/test1.csv")

test.csv has only one column "a" and one number is "656.964"，when I prepare to use "to_csv" then it has changed to 656.9639999. 
I hope you can help solve this problem.

[tseth92]

this is floating point precision problem . See this issue already raised and closed.:
#2069
So, most you can do is pass an argument in to_csv with float_format='%.3f' which will restrict your output to 3 decimal places

[alimcmaster1]

@tseth92 answer should solve your problem. Feel free to reopen @Shanhong