Python将两个列表合并成一个列表

Python将两个列表/数组合并成一个列表/数组

1. extend方法

>>>c1 = ["Red","Green","Blue"]
>>>c2 = ["Orange","Yellow","Indigo"]
>>>c1.extend(c2)
>>>c1 #["Red","Green","Blue","Orange","Yellow","Indigo"] 

2. 直接相加

>>>c1 = ["Red","Green","Blue"]
>>>c2 = ["Orange","Yellow","Indigo"]
>>>c3 = c1 + c2
>>>c3 #  ["Red","Green","Blue","Orange","Yellow","Indigo"]

3. array, 多维数组变成一维数组，flatten()函数用法：
   flatten是numpy.ndarray.flatten的一个函数，即返回一个一维数组。
   flatten只能适用于numpy对象，即array或者mat，普通的list列表不适用。
   a.flatten()：a是个数组，a.flatten()就是把a降到一维，默认是按行的方向降 。
   这种方法多用于复杂算法方面，在此只做了解，按照此方法，我们可以先将列表转换成数组，降维后再tolist()