pandas

图片灰度化例子

import numpy as np
import scipy.misc as sm

import matplotlib.pyplot as mp

image = sm.imread('1.jpg',True).astype(np.uint8)
mp.figure('Image',facecolor='lightgray')
mp.title('lily',fontsize=20)
mp.axis('off')
mp.imshow(image,cmap='gray')
mp.show()

---

---

import numpy as np
import pandas as pd
# 创建DataFrame
df = pd.DataFrame([['Snow','M',22],['Tyrion','M',32],['Sansa','F',18],['Arya','F',14]], columns=['name','gender','age'])
print(df)
#选取多列，gender和age列
# print(df.iloc[:,[1,2]])
df.iloc[0,2]=25
df['score']=[80,98,67,90]
col_name = df.columns.tolist() # 添加列到某行之后,要先转成list
col_name.insert(2,'city')
 # 添加列到尾

df = df.reindex(columns=col_name) # 重新读入列
df['city']=['1省','2省','3省','4省'] # 赋值给city列

new = pd.DataFrame({'name':'lisa','gender':'f','city':'北京','age':25},index=(4,)) # 要插入的行数据
df =df.append(new,ignore_index =True) # 插入一行之后要赋值
print(df)
#df = df.drop(labels='score',axis=1) #删除一列
print(df)
df = df.sort_values(by='score',ascending=False)
print(df)
#
# #读取第1行到第2行的数据
# print(df.loc[1:2])
#
# #读取第1行和第3行，从第0列到第2列,不包括第二列
# print(df.loc[[1,3],['name','gender']])
#
# #读取倒数第3行到倒数第1行的数据
# print(df.iloc[-3:-1,])