Python 从 csv 文件插入

Question

我正在尝试从 csv 文件中插入数据。前两列大小相同。我之前在 txt 文件中使用相同的数据取得了成功，这是我第一次尝试使用 csv 文件。任何帮助，将不胜感激。示例 csv 文件

wave,transmittance
406.06,0.384
420.06,0.398
440.85,0.416
....,.....

import numpy as np
import csv
from scipy import interpolate

# column 0  wavelength
# column 1  transmittance
# .....

with open('CCD.csv','r') as csv_file:
    next(csv_file)
    data = list(csv.reader(csv_file))

x=[column[0] for column in data]
y=[column[1] for column in data]

I = interpolate.InterpolatedUnivariateSpline(x, y)


print(x)

Output:
UFuncTypeError                 
<ipython-input-9-fa767336938e> in <module>
     12 y=[column[1] for column in data]
     13 
---> 14 I = interpolate.InterpolatedUnivariateSpline(x, y)

UFuncTypeError: ufunc 'subtract' did not contain a loop with signature matching types (dtype('<U11'), dtype('<U11')) -> dtype('<U11')

已编辑：

with open('CCD.csv','r') as csv_file:
    reader = csv.reader(csv_file)
    next(csv_file)  # discard header
    data = list(reader)
x1=[column[0] for column in data]
y1=[column[1] for column in data]

I2 = interpolate.InterpolatedUnivariateSpline(x1, y1)
z2 = I2(550)
print(z2)

UFuncTypeError                            Traceback (most recent call last)
<ipython-input-4-a8127aad6fce> in <module>
      6 y1=[column[1] for column in data]
      7 
----> 8 I2 = interpolate.InterpolatedUnivariateSpline(x1, y1)
      9 z2 = I2(550)
     10 print(z2)

UFuncTypeError: ufunc 'subtract' did not contain a loop with signature matching types (dtype('<U11'), dtype('<U11')) -> dtype('<U11')

Answer 1

你很接近。您需要在首次打开文件时创建 reader 对象，然后使用 reader 迭代您的行：

import csv

data = None
with open('CCD.csv', newline='') as csv_file:
    reader = csv.reader(csv_file)
    next(csv_file)  # discard header
    data = list(reader)

x1 = [float(row[0]) for row in data]
y1 = [float(row[1]) for row in data]

print(x1)
print(y1)

我得到：

[406.06, 420.06, 440.85]
[0.384, 0.398, 0.416]

不过，我明白你是如何做到的，只是来自逐行迭代文本文件。很好的尝试！ :)

此外，您不需要指定读取模式'r'，这是默认设置；但对于 CSV 文件，建议在大多数情况下，您希望 newline='' 以便 Python 保留所有换行符（NL、LF、CRLF），就像 CSV reader 处理的那样，根据 CSV 规范。

或者，您可以在阅读 CSV 时构建 x 和 y：

x, y = [], []
with open('CCD.csv', newline='') as csv_file:
    reader = csv.reader(csv_file)
    next(csv_file)  # discard header
    
    for row in reader:
        x.append(float(row[0]))
        y.append(float(row[1]))

print(x)
print(y)

与上面的打印结果相同。

Answer 2

这就是我使用 pandas 进行管理的方式，但我仍然对没有 pandas

的替代方法感到好奇

import pandas as pd

df = pd.read_csv('CCD.csv')

x = df['KAF16200wave'].to_numpy()
y = df['KAF16200transmitence'].to_numpy()

I = interpolate.InterpolatedUnivariateSpline(x, y)

z = I(550)
print("QE:",z)

QE: 0.589681398010309

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