for example, csv file is as below ,(1,2,3) is header!
1,2,3
0,0,0
I read csv file using pd.read_csv and print
import pandas as pd
df = pd.read_csv('./test.csv')
print(df[1])
it occur error key error:1
it seems like that read_csv parse header as string..
is there any way using integer type in dataframe column?
I think more general is cast to columns names to integer by astype:
df = pd.read_csv('./test.csv')
df.columns = df.columns.astype(int)
Another way is first get only first column and use parameter names in read_csv:
import csv
with open("file.csv", "r") as f:
reader = csv.reader(f)
i = np.array(next(reader)).astype(int)
#another way
#i = pd.read_csv("file.csv", nrows=0).columns.astype(int)
print (i)
[1 2 3]
df = pd.read_csv("file.csv", names=i, skiprows=1)
print (df.columns)
Int64Index([1, 2, 3], dtype='int64')
df.columns = [df.columns.get_level_values(0).astype(int), df.columns.get_level_values(1)]
df.columns.set_levels.Skip the header column using skiprows=1 and header=None. This automatically loads in a dataframe with integer headers starting from 0 onwards.
df = pd.read_csv('test.csv', skiprows=1, header=None).rename(columns=lambda x: x + 1)
df
1 2 3
0 0 0 0
The rename call is optional, but if you want your headers to start from 1, you may keep it in.
If you have a MultiIndex, use set_levels to set just the 0th level to integer:
df.columns = df.columns.set_levels(
df.columns.get_level_values(0).astype(int), level=0
)
set_levels is a great option.You can use set_axis in conjunction with a lambda and pd.Index.map
Consider a csv that looks like:
1,1,2,2
a,b,a,b
1,3,5,7
0,2,4,6
Read it like:
df = pd.read_csv('test.csv', header=[0, 1])
df
1 2
a b a b
0 1 3 5 7
1 0 2 4 6
You can pipeline the column setting with integers in the first level like:
df.set_axis(df.columns.map(lambda i: (int(i[0]), i[1])), axis=1, inplace=False)
1 2
a b a b
0 1 3 5 7
1 0 2 4 6
is there any way using integer type in dataframe column?
I find this quite elegant:
df = pd.read_csv('test.csv').rename(columns=int)
Note that int here is the built-in function int().
