如何使用特定输出格式将矩阵（从一个文件读取）写入 python 中的另一个 csv 文件

Question

我有一个 csv 文件，其中包含矩阵格式的数据，示例如下所示：

index,col1,col2,col3,col4,col5,col6
col1_1,1,0.005744233,0.013118052,-0.003772589,0.004284689
col2_1,0.005744233,1,-0.013269414,-0.007132092,0.013950261
col3_1,0.013118052,-0.013269414,1,-0.014029249,-0.00199437
col4_1,-0.003772589,-0.007132092,-0.014029249,1,0.022569309
col5_1,0.004284689,0.013950261,-0.00199437,0.022569309,1

不，我想读取此文件中的数据并将其写入另一个 csv 文件，但我需要的格式是这样的：

col1_1,value,col1
col1_1,value,col2
col1_1,value,col3
.
.
.
col2_1,value,col1
col2_1,value,col2
.
.
.

所以基本上第一个元素将是第一列中的列名，后跟该列的值和第一行中的元素。

我写了这段代码，但它只是写错了格式：

reader = csv.reader(open(IN_FILE, "r"), delimiter=',')
writer = csv.writer(open(OUT_FILE, "w"), delimiter=',')

with open(IN_FILE) as infile:
    with open(OUT_FILE, "w") as outfile:
        reader = csv.reader(infile, delimiter=",")
        writer = csv.writer(outfile, delimiter=",")
        writer.writerow(next(reader))
        for line in reader:
            writer.writerow([line[0],line[1]])

如何在 python 中执行此操作？

Answer 1

试试这个：

reader = csv.reader(open(IN_FILE, "r"), delimiter=',')
writer = csv.writer(open(OUT_FILE, "w"), delimiter=',')

with open(IN_FILE) as infile:
    with open(OUT_FILE, "w") as outfile:
        reader = csv.reader(infile, delimiter=",")
        writer = csv.writer(outfile, delimiter=",")

        first_row = None
        for line in reader:
            if first_row is None:
                first_row = line
            else:
                for index, col in enumerate(first_row[1:]):
                    writer.writerow([line[0],line[index + 1],col])

这似乎有效。尽管您的测试数据看起来缺少 'col6'.

您的初始代码的问题在于它没有遍历每一列的行。

Answer 2

如果您的文件像我假设的那样包含列索引和行索引，那么应该这样做。

old_data = reader
new_data = []

for row in xrange(0,len(old_data)):
    for col in xrange(0,len(row)):
        if (not row == 0 and not col == 0):
            new_data.append([old_data[row][0],old_data[row][col],old_data[0][col]])

writer.writerows(new_data)
csv_file.close()

如何使用特定输出格式将矩阵（从一个文件读取）写入 python 中的另一个 csv 文件

How to write a matrix (read from one file) to another csv file in python with a specific output format

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