python - 如何遍历数据框中每一列的行
问题描述
如果只有 1 个传感器，即如果 col2 和 col3 在下面提供的示例数据中被删除，我当前的代码将运行并生成一个图表，留下一列。
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
d = {'col1': [-2587.944231, -1897.324231,-2510.304231,-2203.814231,-2105.734231,-2446.964231,-2963.904231,-2177.254231, 2796.354231,-2085.304231], 'col2': [-3764.468462,-3723.608462,-3750.168462,-3694.998462,-3991.268462,-3972.878462,3676.608462,-3827.808462,-3629.618462,-1841.758462,], 'col3': [-166.1357692,-35.36576923, 321.4157692,108.9257692,-123.2257692, -10.84576923, -100.7457692, 89.27423077, -211.0857692, 101.5342308]}
df = pd.DataFrame(data=d)
sensors = 3
window_size = 5
dfn = df.rolling(window_size).corr(pairwise = True)
index = df.index #index of values in the data frame.
rows = len(index) #len(index) returns number of rows in the data.
sensors = 3
baseline_num = [0]*(rows) #baseline numerator, by default zero
baseline = [0]*(rows) #initialize baseline value
baseline = DataFrame(baseline)
baseline_num = DataFrame(baseline_num)
v = [None]*(rows) # Initialize an empty array v[] equal to amount of rows in .csv file
s = [None]*(rows) #Initialize another empty array for the slope values for detecting when there is an exposure
d = [0]*(rows)
sensors_on = True #Is the sensor detecting something (True) or not (False).
off_count = 0
off_require = 8 # how many offs until baseline is updated
sensitivity = 1000
for i in range(0, (rows)): #This iterates over each index value, i.e. each row, and sums the values and returns them in list format.
v[i] = dfn.loc[i].to_numpy().sum() - sensors
for colname,colitems in df.iteritems():
for rownum,rowitem in colitems.iteritems():
#d[rownum] = dfone.loc[rownum].to_numpy()
#d[colname][rownum] = df.loc[colname][rownum]
if v[rownum] >= sensitivity:
sensors_on = True
off_count = 0
baseline_num[rownum] = 0
else:
sensors_on = False
off_count += 1
if off_count == off_require:
for x in range(0, (off_require)):
baseline_num[colname][rownum] += df[colname][rownum - x]
elif off_count > off_require:
baseline_num[colname][rownum] += baseline_num[colname][rownum - 1] + df[colname][rownum] - (df[colname][rownum - off_require]) #this loop is just an optimization, one calculation per loop once the first calculation is established
baseline[colname][rownum] = ((baseline_num[colname][rownum])//(off_require)) #mean of the last "off_require" points
dfx = DataFrame(v, columns =['Sensor Correlation']) #converts the summed correlation tables back from list format to a DataFrame, with the sole column name 'Sensor Correlation'
dft = pd.DataFrame(baseline, columns =['baseline'])
dft = dft.astype(float)
dfx.plot(figsize=(50,25), linewidth=5, fontsize=40) # plots dfx dataframe which contains correlated and summed data
dft.plot(figsize=(50,25), linewidth=5, fontsize=40)
基本上，我想仅针对此循环遍历每一列，而不是生成 1 个图形：
for colname,colitems in df.iteritems():
for rownum,rowitem in colitems.iteritems():
#d[rownum] = dfone.loc[rownum].to_numpy()
#d[colname][rownum] = df.loc[colname][rownum]
if v[rownum] >= sensitivity:
sensors_on = True
off_count = 0
baseline_num[rownum] = 0
else:
sensors_on = False
off_count += 1
if off_count == off_require:
for x in range(0, (off_require)):
baseline_num[colname][rownum] += df[colname][rownum - x]
elif off_count > off_require:
baseline_num[colname][rownum] += baseline_num[colname][rownum - 1] + df[colname][rownum] - (df[colname][rownum - off_require]) #this loop is just an optimization, one calculation per loop once the first calculation is established
我已经尝试了其他问题的其他解决方案，但似乎都没有解决这个问题。到目前为止，我已经尝试过多次转换为列表和元组之类的东西，然后像这样称呼它们：
baseline_num[i,column] += d[i - x,column]
也
baseline_num[i][column += d[i - x][column]
同时使用迭代循环
for column in columns
但是，无论我如何安排解决方案，总是存在一些期望整数或切片索引的关键错误，以及其他错误。有关实际数据的一列的预期/可能输出，请参见图片。输入参数不同（灵敏度值和 off_require 在不同情况下会有所不同。）其中一个不起作用的解决方案是来自此链接的循环方法：
https://www.geeksforgeeks.org/iterating-over-rows-and-columns-in-pandas-dataframe/
我还尝试使用 ititems 作为外循环创建一个循环。这也不起作用。
下面是各种灵敏度值的可能图形输出的链接，以及我实际数据集中的窗口，只有一列。（即我手动删除了其他列，并仅使用当前程序绘制了一个）
如果我遗漏了任何有助于解决此问题的内容，请告诉我，以便我立即纠正。
请参阅这张图片以获取我原来的 df.head： df.head
解决方案
你试过了吗，
for colname,colitems in df.iteritems():
for rownum,rowitem in colitems.iteritems():
print(df[colname][rownum])
第一个循环遍历所有列，第二个循环遍历该列的所有行。
编辑：
从我们下面的对话中，我认为您的基线和 df 数据框没有相同的列名，因为您创建它们的方式以及访问元素的方式。
我的建议是您创建基线数据框作为您的 df 数据框的副本，并从那里编辑其中的信息。
编辑：
我已经设法让你的代码在 1 个循环中工作，但是我遇到了一个索引错误，我不确定你的优化函数做了什么，但我认为这是导致它的原因，看看。
就是这部分baseline_num[colname][rownum - 1]，我猜在第二个循环中，因为你执行 rownum (0) -1，你得到索引 -1。您需要更改它，以便在第一个循环中 rownum 为 1 或其他内容，我不确定您要在那里做什么。
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
d = {'col1': [-2587.944231, -1897.324231,-2510.304231,-2203.814231,-2105.734231,-2446.964231,-2963.904231,-2177.254231, 2796.354231,-2085.304231], 'col2': [-3764.468462,-3723.608462,-3750.168462,-3694.998462,-3991.268462,-3972.878462,3676.608462,-3827.808462,-3629.618462,-1841.758462,], 'col3': [-166.1357692,-35.36576923, 321.4157692,108.9257692,-123.2257692, -10.84576923, -100.7457692, 89.27423077, -211.0857692, 101.5342308]}
df = pd.DataFrame(data=d)
sensors = 3
window_size = 5
dfn = df.rolling(window_size).corr(pairwise = True)
index = df.index #index of values in the data frame.
rows = len(index) #len(index) returns number of rows in the data.
sensors = 3
baseline_num = [0]*(rows) #baseline numerator, by default zero
baseline = [0]*(rows) #initialize baseline value
baseline = pd.DataFrame(df)
baseline_num = pd.DataFrame(df)
#print(baseline_num)
v = [None]*(rows) # Initialize an empty array v[] equal to amount of rows in .csv file
s = [None]*(rows) #Initialize another empty array for the slope values for detecting when there is an exposure
d = [0]*(rows)
sensors_on = True #Is the sensor detecting something (True) or not (False).
off_count = 0
off_require = 8 # how many offs until baseline is updated
sensitivity = 1000
for i in range(0, (rows)): #This iterates over each index value, i.e. each row, and sums the values and returns them in list format.
v[i] = dfn.loc[i].to_numpy().sum() - sensors
for colname,colitems in df.iteritems():
#print(colname)
for rownum,rowitem in colitems.iteritems():
#print(rownum)
#display(baseline[colname][rownum])
#d[rownum] = dfone.loc[rownum].to_numpy()
#d[colname][rownum] = df.loc[colname][rownum]
if v[rownum] >= sensitivity:
sensors_on = True
off_count = 0
baseline_num[rownum] = 0
else:
sensors_on = False
off_count += 1
if off_count == off_require:
for x in range(0, (off_require)):
baseline_num[colname][rownum] += df[colname][rownum - x]
elif off_count > off_require:
baseline_num[colname][rownum] += baseline_num[colname][rownum - 1] + df[colname][rownum] - (df[colname][rownum - off_require]) #this loop is just an optimization, one calculation per loop once the first calculation is established
baseline[colname][rownum] = ((baseline_num[colname][rownum])//(off_require)) #mean of the last "off_require" points
print(baseline[colname][rownum])
dfx = pd.DataFrame(v, columns =['Sensor Correlation']) #converts the summed correlation tables back from list format to a DataFrame, with the sole column name 'Sensor Correlation'
dft = pd.DataFrame(baseline, columns =['baseline'])
dft = dft.astype(float)
dfx.plot(figsize=(50,25), linewidth=5, fontsize=40) # plots dfx dataframe which contains correlated and summed data
dft.plot(figsize=(50,25), linewidth=5, fontsize=40)
我的输出看起来像这样，
-324.0
-238.0
-314.0
-276.0
-264.0
-306.0
-371.0
-806.0
638.0
-412.0
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
/usr/local/lib/python3.7/dist-packages/pandas/core/indexes/range.py in get_loc(self, key, method, tolerance)
354 try:
--> 355 return self._range.index(new_key)
356 except ValueError as err:
ValueError: -1 is not in range
The above exception was the direct cause of the following exception:
KeyError Traceback (most recent call last)
3 frames
/usr/local/lib/python3.7/dist-packages/pandas/core/indexes/range.py in get_loc(self, key, method, tolerance)
355 return self._range.index(new_key)
356 except ValueError as err:
--> 357 raise KeyError(key) from err
358 raise KeyError(key)
359 return super().get_loc(key, method=method, tolerance=tolerance)
KeyError: -1