python中函数join(),split(),strip()

1.join(),可以对str、lsit、tuple、dict用，但是不能对int，

str.join(sequence)

t1 = ("a", "b", "c")
s1 = "abc"
l1 = ["a", "b", "c"]
d1 = {"a": 1, "b": 2, "c": 3}
n1 = 123456

print(",".join(t1), type(",".join(t1)))
print(",".join(s1), type(",".join(s1)))
print(",".join(l1), type(",".join(l1)))
print(",".join(d1), type(",".join(d1)))
print(",".join(n1), type(",".join(n1)))

a,b,c <class 'str'>
a,b,c <class 'str'>
a,b,c <class 'str'>
a,b,c <class 'str'>
TypeError: can only join an iterable

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2.split()分割

str.split('第一个参数为以什么分割', '第二个参数是分割多少次，不写默认全部分割' )

输出结果为列表

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3.stript()去除字符串头尾的指定字符，lstript()去除字符串头的指定字符，rstript()去除字符串尾的指定字符，不写默认去除空格

str.strip([chars]);
str.lstrip([chars]);
str.rstrip([chars]);

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4.判断一个列表中的每个元素是不是另一个列表中的元素

In [2]: a = [1, 2]

In [3]: b = [1, 2, 3]

In [4]: set(a) < set(b)
Out[4]: True

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4.Python字典中的值为列表或字典的构造方法

https://blog.csdn.net/buside/article/details/81323871

dic = {}

dic.setdefault(key,[]).append(value)

*********示例如下******

>>dic.setdefault('a',[]).append(1)

>>dic.setdefault('a',[]).append(2)

>>dic