Brief introduction to the usage of iloc in dataframe

grammar ：df.iloc[: , :]

1, The preceding colon represents the selected row , The following colon represents how many columns are selected

2, The principle of left closing and right opening

Explain by a set of columns

df.iloc[0:1 , :]      # Select the first 1 That's ok 
df.iloc[0, :]         # Select the first 1 That's ok 
df.iloc[1:3 , :]      # Select the first 2 Go to the first place 4 That's ok , The first 4 Line unselected 


df.iloc[: , 1:2]      # Select the first 2 Column 
df.iloc[:, 1]         # Select the first 2 Column 
df.iloc[: , 2:4]      # Select the first 3 Column to the first 5 Column , The first 5 Column is not selected 


df.iloc[1:3 , 2:4]    # Select the first 2 Go to the first place 4 That's ok , And No 3 Column to the first 5 Column .3 That's ok ,5 Column is not selected , The principle of left closing and right opening