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python - json 文件只能采用整数或切片格式而不是字符串

问题描述

我在运行下面的代码时遇到问题，在 t one_freq =tone_map[tone_name 行它会带来错误，即列表索引必须是整数或切片而不是字符串

评论音调网站上的 Json 样本是

[
 {
   "432": "Note",
   "434": "Frequency (Hz)",
   "436": "Wavelength (cm)",
   "438": "",
   "440": "",
   "442": "",
   "444": "",
   "446": ""
  },
 {
   "432": "C0",
   "434": "16.35",
   "436": "2109.89",
   "438": "",
   "440": "",
   "442": "",
   "444": "",
   "446": ""
  },
 {
   "432": "C#0/Db0",
   "434": "17.32",
   "436": "1991.47",
   "438": "",
   "440": "",
   "442": "",
   "444": "",
   "446": ""
  },

用于合成音调以生成音乐的 python 代码是 this.i 已将http://www.phy.mtu.edu/~suits/notefreqs.html上的 html 表转换为正在使用但表示它有的 json 文件为整数或切片

import json

import numpy as np
import matplotlib.pyplot as plt
from scipy.io.wavfile import write

# Synthesize the tone based on the input parameters
def tone_synthesizer(freq, duration, amplitude=1.0, sampling_freq=44100):
# Construct the time axis 
    time_axis = np.linspace(0, duration, duration * sampling_freq)

# Construct the audio signal
    signal = amplitude * np.sin(2 * np.pi * freq * time_axis)

    return signal.astype(np.int16) 

if __name__=='__main__':
    # Names of output files
    file_tone_single = 'generated_tone_single.wav'
    file_tone_sequence = 'generated_tone_sequence.wav'

    # Source: http://www.phy.mtu.edu/~suits/notefreqs.html
    mapping_file = 'tone_mapping.json'

   # Load the tone to frequency map from the mapping file
with open(mapping_file, 'r') as f:
    tone_map = json.loads(f.read())

# Set input parameters to generate 'F' tone
tone_name = 'F'
duration = 3     # seconds
amplitude = 12000
sampling_freq = 44100    # Hz

# Extract the tone frequency
tone_freq = tone_map[tone_name]

# Generate the tone using the above parameters
synthesized_tone = tone_synthesizer(tone_freq, duration, amplitude, sampling_freq)

# Write the audio signal to the output file
write(file_tone_single, sampling_freq, synthesized_tone)

# Define the tone sequence along with corresponding durations in seconds
tone_sequence = [('G', 0.4), ('D', 0.5), ('F', 0.3), ('C', 0.6), ('A', 0.4)]

# Construct the audio signal based on the above sequence 
signal = np.array([])
for item in tone_sequence:
    # Get the name of the tone 
    tone_name = item[0]

    # Extract the corresponding frequency of the tone
    freq = tone_map[tone_name]

    # Extract the duration
    duration = item[1]

    # Synthesize the tone
    synthesized_tone = tone_synthesizer(freq, duration, amplitude, sampling_freq)

    # Append the output signal
    signal = np.append(signal, synthesized_tone, axis=0)

# Save the audio in the output file
write(file_tone_sequence, sampling_freq, signal)

标签： python

解决方案

从python文档：

json.loads(s[, encoding[, cls[, object_hook[, parse_float[, parse_int[, parse_constant[, object_pairs_hook[, **kw]]]]]]]])

使用此转换表将 s（包含 JSON 文档的 str 或 unicode 实例）反序列化为 Python 对象。

如果 s 是 str 实例并且使用基于 ASCII 的编码而不是 UTF-8（例如 latin-1）进行编码，则必须指定适当的编码名称。不允许使用不基于 ASCII 的编码（例如 UCS-2），应首先将其解码为 un​​icode。

从错误中可以理解，tone_map是一个列表。尝试这个：

for i in tone_map: tone_freq = i[tone_name]

将tone_freq 存储在列表中并使用它

tone_frequencies = list() for i in tone_map: tone_frequencies.append(i)

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