1.dict.get()
from numpy import *
labels=['a','b','d','n','s']
dict={}
a=labels[3];
b=labels[4];
dict[a]=dict.get(a,0)+1
dict[b]=dict.get(a,2)+1
print(dict)
{'n': 1, 's': 2}
2.sorted(),itemgetter()
#
from math import log
import operator
classCount={0:10,3:9,1:12}
sortedClassCount = sorted(classCount.items(), key=operator.itemgetter(0), reverse=True)
print(sortedClassCount)
[(3, 9), (1, 12), (0, 10)]
#
import operator
c = [('john', 'A', 15), ('jane', 'B', 12), ('dave', 'A', 10)]
#reverse降序排列,默认true。取C中一二维进行降序排列(字母和数字)
d=sorted(c, key=operator.itemgetter(1,2),reverse=True)
print(d)
[('dave', 'A', 10), ('john', 'A', 15), ('jane', 'B', 12)]
#
import operator
classCount={0:10,3:9,1:12}
sortedClassCount = sorted(classCount.items(), key=operator.itemgetter(0), reverse=True)
print(sortedClassCount)
[(3, 9), (1, 12), (0, 10)]
3.tile()
from numpy import *
a=[[1,2,3],[4,5,6]]
b=tile(a,(2,1))
print(b)
[[1 2 3]
[4 5 6]
[1 2 3]
[4 5 6]]
4.get()
https://blog.csdn.net/weixin_38705903/article/details/79231551
5.strip()&split()
https://www.cnblogs.com/yyxayz/p/4034299.html
6.readlines&readline