Question

我有一个csv文件，它只有一列，作为我的输入。

我使用该输入来查找输出。我有多个输出，我需要在另一个csv文件中的那些输出。

任何人都可以建议我如何做到这一点？

以下是代码：

import urllib.request
jd = {input 1}
// 
  Some Codes to find output - a,b,c,d,e
//
** Code to write output to a csv file.
** Repeat the code with next input of input csv file.


 Input CSV File has only a single column and is represented below: 
 1
 2
 3
 4
 5 

 Output would in a separate csv in a given below format :
  It would be in multiple rows and multiple columns format.

 a    b     c    d      e

Answer 1

这是一个简单的例子：

data.csv是一个包含一列和多行的csv。

results.csv包含输入的平均值和中位数，是一个包含1行和2列的csv（平均值在第1列，中位数在第2列）

示例：

import numpy as np
import pandas as pd
import csv

#load the data
data = pd.read_csv("data.csv", header=None)

#calculate things for the 1st column that has the data
calculate_mean = [np.mean(data.loc[:,0])]
calculate_median = [np.median(data.loc[:,0])]
results = [calculate_mean, calculate_median]

#write results to csv
row = []
for result in results:
    row.append(result)

with open("results.csv", "wb") as file:
   writer = csv.writer(file)
   writer.writerow(row)

Answer 2

我认为您需要read_csv才能将文件读取到Series和to_csv，以便在Series.iteritems的循环中将输出Series写入文件。

#file content
1
3
5

s = pd.read_csv('file', squeeze=True, names=['a'])
print (s)
0    1
1    3
2    5
Name: a, dtype: int64

for i, val in s.iteritems():
    #print (val)
    #some operation with scalar value val
    df = pd.DataFrame({'a':np.arange(val)})
    df['a'] = df['a'] * 10
    print (df)
    #write to csv, file name by val
    df.to_csv(str(val) + '.csv', index=False)

   a
0  0

    a
0   0
1  10
2  20

    a
0   0
1  10
2  20
3  30
4  40

Answer 3

在伪代码中，你会做这样的事情：

for each_file in a_folder_that_contains_csv:  # go through all the `inputs` - csv files
    with open(each_file) as csv_file, open(other_file) as output_file:  # open each csv file, and a new csv file
        process_the_input_from_each_csv  # process the data you read from the csv_file
        export_to_output_file  # export the data to the new csv file

现在，我不会写一个完整的例子，因为当你有一些问题时，你最好开始挖掘并询问具体的问题。你现在只是问：为我写这个，因为我不懂Python 。

如何在Python中读取和写入CSV文件

3 个答案: