pd.dataframe.append

官方文档介绍链接：append方法介绍

DataFrame.append(other, ignore_index=False, verify_integrity=False, sort=None)

功能说明：向dataframe对象中添加新的行，如果添加的列名不在dataframe对象中，将会被当作新的列进行添加

other：DataFrame、series、dict、list这样的数据结构
ignore_index：默认值为False，如果为True则不使用index标签
verify_integrity ：默认值为False，如果为True当创建相同的index时会抛出ValueError的异常
sort：boolean，默认是None，该属性在pandas的0.23.0的版本才存在。

append添加字典

    import pandas as pd

data <span class="token operator">=</span> pd<span class="token punctuation">.</span>DataFrame<span class="token punctuation">(</span><span class="token punctuation">)</span>
a <span class="token operator">=</span> <span class="token punctuation">{<!-- --></span><span class="token string">"x"</span><span class="token punctuation">:</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token string">"y"</span><span class="token punctuation">:</span><span class="token number">2</span><span class="token punctuation">}</span>
data <span class="token operator">=</span> data<span class="token punctuation">.</span>append<span class="token punctuation">(</span>a<span class="token punctuation">,</span>ignore_index<span class="token operator">=</span><span class="token boolean">True</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span>

append添加series

如果不添加ignore_index=True，会报错提示TypeError: Can only append a Series if ignore_index=True or if the Series has a name，如果不添加ignore_index=True，也可以改成以下代码

    import pandas as pd

data <span class="token operator">=</span> pd<span class="token punctuation">.</span>DataFrame<span class="token punctuation">(</span><span class="token punctuation">)</span>
series <span class="token operator">=</span> pd<span class="token punctuation">.</span>Series<span class="token punctuation">(</span><span class="token punctuation">{<!-- --></span><span class="token string">"x"</span><span class="token punctuation">:</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token string">"y"</span><span class="token punctuation">:</span><span class="token number">2</span><span class="token punctuation">}</span><span class="token punctuation">,</span>name<span class="token operator">=</span><span class="token string">"a"</span><span class="token punctuation">)</span>
data <span class="token operator">=</span> data<span class="token punctuation">.</span>append<span class="token punctuation">(</span>series<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>data<span class="token punctuation">)</span>

注意：当dataframe使用append方法添加series的时候，必须要设置name，设置name名称将会作为index的name。

append添加list

    data = pd.DataFrame()a = [1,2,3]data = data.append(a)print(data)

如果list是一维的，则是以列的形式来进行添加，如果list是二维的则是以行的形式进行添加的，如果是三维的则只添加一个值

    data = pd.DataFrame()a = [[[1,2,3]]]data = data.append(a)print(data)

注意：在多次使用append方法追加数据的时候，可能会出现相同的index

    data = pd.DataFrame()a = [[1,2,3],[4,5,6]]data = data.append(a)a = [[7,8,9],[10,11,12]]data = data.append(a)print(data)

如果想要添加的index不出现重复的情况，可以通过设置ignore_index=True来避免