Grammar format ：
give an example ：df[ df[ " English "] > 60]
df as follows
1, Find English scores greater than 60 The line of .
df = df[df[" English "] > 60] # English scores are greater than 60 The line of
print(df)
2, Find a math score equal to 90 The line of
df = df[df[" mathematics "] == 90] # Find a math score equal to 90 The line of
print(df)
3, Find a physics score greater than 60, And the score of biology is greater than 80 The line of .（ Pay attention to parentheses ）
df = df[(df[" Physics "] > 60) & (df[" biological "] > 80)]
print(df)
