如何使用matplotlib子图和pandas制作多线图?

时间:2016-07-13 00:29:27

标签: python pandas matplotlib plot subplot

我在编码方面相当新(完全自学成才),并且在我作为癌症实验室研究助理的工作中开始使用它。我需要一些帮助在matplot lab中设置一些折线图。

我有一个数据集,其中包括约80名患者的nextgen测序数据。对于每位患者,我们有不同的分析时间点,检测到不同的基因(40个),以及该基因的相关%突变。

我的目标是编写两个脚本,一个将生成一个"由患者"该图将是具有y-%突变,x-测量时间的线图,并且对于由每个患者的相关基因产生的所有线将具有不同的颜色线。第二个图将是" by gene",其中我将有一个图包含不同的颜色线,代表该特定基因的每个不同患者的x / y值。

以下是上述脚本的1个编号的示例数据框:

gene    yaxis   xaxis   pt# gene#
ASXL1-3 34  1   3   1
ASXL1-3 0   98  3   1
IDH1-3  24  1   3   11
IDH1-3  0   98  3   11
RUNX1-3 38  1   3   21
RUNX1-3 0   98  3   21
U2AF1-3 33  1   3   26
U2AF1-3 0   98  3   26

我已经设置了一个groupby脚本,当我迭代它时,为每个患者的每个基因时间点提供一个数据帧。

grouped = df.groupby('pt #')
for groupObject in grouped:
    group = groupObject[1]

对于患者1,这给出了以下输出:

        y     x   gene  patientnumber patientgene  genenumber  dxtotransplant  \
0    40.0  1712  ASXL1              1     ASXL1-1           1            1857   
1    26.0  1835  ASXL1              1     ASXL1-1           1            1857   
302   7.0  1835  RUNX1              1     RUNX1-1          21            1857   

我需要帮助编写一个脚本来创建上述任何一个图。使用bypatient示例,我的一般想法是我需要为患者的每个基因创建一个不同的子图,其中每个子图是由该基因代表的线图。

使用matplotlib这就是我所得到的:

plt.figure()

grouped = df.groupby('patient number')

for groupObject in grouped:
    group = groupObject[1]
    df = group #may need to remove this
    for element in range(len(group)): 
        xs = np.array(df[df.columns[1]]) #"x" column
        ys= np.array(df[df.columns[0]]) #"y" column
        gene = np.array(df[df.columns[2]])[element] #"gene" column
        plt.subplot(1,1,1) 
        plt.scatter(xs,ys, label=gene)
        plt.plot(xs,ys, label=gene)
        plt.legend()
    plt.show()

这会产生以下输出:

enter image description here

在此输出中,圆圈线不应连接到其他2个点。在这种情况下,这是患者1,具有以下数据点:

x       y   gene
1712    40  ASXL1
1835    26  ASXL1
1835    7   RUNX1

使用seaborn我已经使用此代码接近我想要的图形:

grouped = df.groupby(['patientnumber'])
for groupObject in grouped:
    group = groupObject[1]
    g = sns.FacetGrid(group, col="patientgene", col_wrap=4, size=4, ylim=(0,100))  
    g = g.map(plt.scatter, "x", "y", alpha=0.5)
    g = g.map(plt.plot, "x", "y", alpha=0.5)
    plt.title= "gene:%s"%element

使用此代码我得到以下内容:

如果我调整行:

g = sns.FacetGrid(group, col="patientnumber", col_wrap=4, size=4, ylim=(0,100))

我得到以下结果:

enter image description here

正如您在第二个示例中所看到的,该图正在处理我的绘图中的每个点,就好像它们来自同一行(但实际上它们是4个单独的行)。

我如何调整我的迭代,以便每个患者基因在同一图表上被视为一个单独的行?

1 个答案:

答案 0 :(得分:1)

我写了一个subplot函数,可以帮到你。我修改了数据以帮助说明绘图功能。

gene,yaxis,xaxis,pt #,gene #
ASXL1-3,34,1,3,1
ASXL1-3,3,98,3,1
IDH1-3,24,1,3,11
IDH1-3,7,98,3,11
RUNX1-3,38,1,3,21
RUNX1-3,2,98,3,21
U2AF1-3,33,1,3,26
U2AF1-3,0,98,3,26
ASXL1-3,39,1,4,1
ASXL1-3,8,62,4,1
ASXL1-3,0,119,4,1
IDH1-3,27,1,4,11
IDH1-3,12,62,4,11
IDH1-3,1,119,4,11
RUNX1-3,42,1,4,21
RUNX1-3,3,62,4,21
RUNX1-3,1,119,4,21
U2AF1-3,16,1,4,26
U2AF1-3,1,62,4,26
U2AF1-3,0,119,4,26

这是子绘图功能......带有一些额外的铃声和口哨声:)

def plotByGroup(df, group, xCol, yCol, title = "", xLabel = "", yLabel = "", lineColors = ["red", "orange", "yellow", "green", "blue", "purple"], lineWidth = 2, lineOpacity = 0.7, plotStyle = 'ggplot', showLegend = False):
    """
    Plot multiple lines from a Pandas Data Frame for each group using DataFrame.groupby() and MatPlotLib PyPlot.
    @params
        df          - Required  - Data Frame    - Pandas Data Frame
        group       - Required  - String        - Column name to group on           
        xCol        - Required  - String        - Column name for X axis data
        yCol        - Required  - String        - Column name for y axis data
        title       - Optional  - String        - Plot Title
        xLabel      - Optional  - String        - X axis label
        yLabel      - Optional  - String        - Y axis label
        lineColors  - Optional  - List          - Colors to plot multiple lines
        lineWidth   - Optional  - Integer       - Width of lines to plot
        lineOpacity - Optional  - Float         - Alpha of lines to plot
        plotStyle   - Optional  - String        - MatPlotLib plot style
        showLegend  - Optional  - Boolean       - Show legend
    @return
        MatPlotLib Plot Object

    """
    # Import MatPlotLib Plotting Function & Set Style
    from matplotlib import pyplot as plt
    matplotlib.style.use(plotStyle)
    figure = plt.figure()                   # Initialize Figure
    grouped = df.groupby(group)             # Set Group
    i = 0                                   # Set iteration to determine line color indexing
    for idx, grp in grouped:
        colorIndex = i % len(lineColors)    # Define line color index
        lineLabel = grp[group].values[0]    # Get a group label from first position
        xValues = grp[xCol]                 # Get x vector
        yValues = grp[yCol]                 # Get y vector
        plt.subplot(1,1,1)                  # Initialize subplot and plot (on next line)
        plt.plot(xValues, yValues, label = lineLabel, color = lineColors[colorIndex], lw = lineWidth, alpha = lineOpacity)
        # Plot legend
        if showLegend:
            plt.legend()
        i += 1
    # Set title & Labels
    axis = figure.add_subplot(1,1,1)
    axis.set_title(title)
    axis.set_xlabel(xLabel)
    axis.set_ylabel(yLabel)
    # Return plot for saving, showing, etc.
    return plt

并使用它......

import pandas

# Load the Data into Pandas
df = pandas.read_csv('data.csv')    

#
# Plotting - by Patient
#

# Create Patient Grouping
patientGroup = df.groupby('pt #')

# Iterate Over Groups
for idx, patientDF in patientGroup:
    # Let's give them specific titles
    plotTitle = "Gene Frequency over Time by Gene (Patient %s)" % str(patientDf['pt #'].values[0])
    # Call the subplot function
    plot = plotByGroup(patientDf, 'gene', 'xaxis', 'yaxis', title = plotTitle, xLabel = "Days", yLabel = "Gene Frequency")
    # Add Vertical Lines at Assay Timepoints
    timepoints = set(patientDf.xaxis.values)
    [plot.axvline(x = timepoint, linewidth = 1, linestyle = "dashed", color='gray', alpha = 0.4) for timepoint in timepoints]
    # Let's see it
    plot.show()

enter image description here

当然,我们可以通过基因做同样的事情。

#
# Plotting - by Gene
#

# Create Gene Grouping
geneGroup   = df.groupby('gene')

# Generate Plots for Groups
for idx, geneDF in geneGroup:
    plotTitle = "%s Gene Frequency over Time by Patient" % str(geneDf['gene'].values[0])
    plot = plotByGroup(geneDf, 'pt #', 'xaxis', 'yaxis', title = plotTitle, xLab = "Days", yLab = "Frequency")
    plot.show()

enter image description here

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