pandas对csv文件的相关操作

╰半橙微兮° 2023-06-19 06:53 1阅读 0赞

# pandas csv文件相关函数和相关操作 #

0 注意:inplace = True表示当前操作已经在应用到当前环境中了,比如删除一行,然后inplace = True之后,下次再使用就没有删除的这一行了

**1 np.set\_printoptions(threshold=np.inf) numpy时使用最大数显示  
2 data = pd.read\_csv(r"data.csv",nrows=5) 加载固定行数数据  
3 data.head(2) 显示固定行数  
4 data\[“index”\].values\[0:10\] \#标签为index的列数据  
5 data.columns.values 显示所有标签  
6 data.drop(data.index\[1\],inplace=True) 删除第一行  
7 data1.drop\_duplicates(‘name’, inplace=True) 删除"name"中的重复数据  
8 data.rename(columns=\{‘index-given’:‘u7777777’,‘wgsize’:‘wwww’\}, inplace = True) 替换列表列标签  
9 data.insert(5,‘typeSmallSmall’,insert1) \#在第五个空子(0,1,2,3,4,5)插入列名字为typeSmallSmall的数据insert1**

import pandas as pd
    import numpy as np
    np.set_printoptions(threshold=np.inf) #最大数显示

# data = pd.read_csv(r"data.csv",nrows=5) #加载固定行数
    data = pd.read_csv(r"data.csv")
    # data

data.head(2) #显示前五行

<table> 
 <thead> 
  <tr> 
   <th></th> 
   <th>index</th> 
   <th>index1</th> 
   <th>index2</th> 
   <th>index3</th> 
   <th>index4</th> 
   <th>index5</th> 
   <th>index6</th> 
   <th>index7</th> 
   <th>index8</th> 
   <th>index9</th> 
   <th>index10</th> 
   <th>index11</th> 
   <th>index12</th> 
   <th>index13</th> 
   <th>index14</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>0</td> 
   <td>0</td> 
   <td>0</td> 
   <td>default</td> 
   <td>98</td> 
   <td>8</td> 
   <td>13</td> 
   <td>11</td> 
   <td>2</td> 
   <td>0</td> 
   <td>2048</td> 
   <td>255</td> 
   <td>0.000</td> 
   <td>0.249</td> 
   <td>2048</td> 
   <td>255</td> 
  </tr> 
  <tr> 
   <td>1</td> 
   <td>1</td> 
   <td>1</td> 
   <td>default</td> 
   <td>12</td> 
   <td>2</td> 
   <td>6</td> 
   <td>0</td> 
   <td>6</td> 
   <td>0</td> 
   <td>131072</td> 
   <td>256</td> 
   <td>0.288</td> 
   <td>0.250</td> 
   <td>131072</td> 
   <td>256</td> 
  </tr> 
 </tbody> 
</table>

print(data["index"].values[0:10]) #标签为index的列数据

[0 1 2 3 4 5 6 7 8 9]

print(data.columns.values) #第一行,所有标签

['index' 'index1' 'index2' 'index3' 'index4' 'index5' 'index6' 'index7'
     'index8' 'index9' 'index10' 'index11' 'index12' 'index13' 'index14']

print(data["index1"].index[1])
    data.drop(data.index[1],inplace=True) #直接删除csv的数据中的第某一行行
    print(data["index1"].index[1])

1
    2

data1 = pd.read_csv(r"data1.csv")
    print(len(data1["name"]))
    data1.drop_duplicates('name', inplace=True) #删除"name"中的重复数据
    print(len(data1["name"]))
    data1.to_csv(r"data2.csv")

25
    20

print(data.columns.values)
    data.drop(['index2'],axis=1,inplace=True) #删除列 index
    print(data.columns.values)

['index' 'index1' 'index2' 'index3' 'index4' 'index5' 'index6' 'index7'
     'index8' 'index9' 'index10' 'index11' 'index12' 'index13' 'index14']
    ['index' 'index1' 'index3' 'index4' 'index5' 'index6' 'index7' 'index8'
     'index9' 'index10' 'index11' 'index12' 'index13' 'index14']

print(data.columns.values)
    data.rename(columns={ 'index3':'u7777777','index1':'wwww'}, inplace = True) #替换列表列标签
    print(data.columns.values)

['index' 'index1' 'index3' 'index4' 'index5' 'index6' 'index7' 'index8'
     'index9' 'index10' 'index11' 'index12' 'index13' 'index14']
    ['index' 'wwww' 'u7777777' 'index4' 'index5' 'index6' 'index7' 'index8'
     'index9' 'index10' 'index11' 'index12' 'index13' 'index14']

insert1 = data["u7777777"].values
    data.insert(5,'typeSmallSmall',insert1) #在第五个空子(0,1,2,3,4,5)插入列名字为typeSmallSmall的数据insert1
    print(data.columns.values)

['index' 'wwww' 'u7777777' 'index4' 'index5' 'typeSmallSmall' 'index6'
     'index7' 'index8' 'index9' 'index10' 'index11' 'index12' 'index13'
     'index14']