np.py

#coding=utf-8
'''
numpy.finfo(numpy.float64)
Out[407]: finfo(resolution=1e-15, min=-1.7976931348623157e+308, max=1.7976931348623157e+308, dtype=float64)

n=932246047*39821*431*(2**966)+1

f.max-f.resolution*(n-1)==f.max
f.max-f.resolution*(n  )!=f.max


1.7976931348623158e+308 == 1.7976931348623157e+308
1.7976931348623159e+308 == inf

'''
import sys,pathlib				# *.py  /qgb   /[gsqp]
gsqp=pathlib.Path(__file__).absolute().parent.parent.absolute().__str__()
if gsqp not in sys.path:sys.path.append(gsqp)#py3 works
from qgb import py
U,T,N,F=py.importUTNF()


import numpy  # as np
#True False array。 




def test():
	a = (a < 255).astype(numpy.int_) # <255 变 1， 255及以上 变0
	a[:,6] # 获取 第 6 列
	
def plot(x,*ys,dys=None,markersize=1,font_size=8):
	import matplotlib.pyplot as plt
	fig,ax = plt.subplots(figsize=(8,8))
	fig.subplots_adjust(
		top=1.0,
		bottom=0.034,
		left=0.033,
		right=1.0,
		hspace=0.2,
		wspace=0.2
	)
	plt.rc('font',size=font_size)
	if not ys and dys:ys=dys
	for k,y in U.iter_kv(ys):
		plt.plot(x,y,'o',label=py.str(k),markersize=markersize)
	plt.legend();
	
	
	plt.show()
	
	
def two_point_line_function(*points,plot=True):
	''' #(x1y1,x2y2,...):
	
	
Decimal('166.36363220214844') # UFuncTypeError: Cannot cast ufunc 'lstsq_n' input 0 from dtype('O') to dtype('float64') with casting rule 'same_kind'
float()转换 解决这个问题
	
'''	
	import numpy as np
	import numpy.linalg as LA
	t=U.col(points,0)
	y=U.col(points,1)
	A=np.c_[t, np.ones_like(t)]
	#print(np.ones_like(t))
	a,b=LA.lstsq(A,y,rcond=None)[0]
	#####
	if b<0:sop=''
	else  :sop='+'
	print(f'y = {a} x {sop} {b}');
		
	sf=f'y={py.round(a,3)}*x{sop}{py.round(b,3)}'
	print(sf)
	if plot:
		import matplotlib.pyplot as plt
		plt.rc('font',size=16)
		plt.plot(t,y,'o',label='Original data',markersize=5)
		plt.plot(t,A.dot([a,b]),'r',label=sf)
		plt.legend();
		
		# ax=plt.gca()
		# ax.format_coord = lambda x,y:f'x={x} y={y}' # 好像 x,y 鼠标 标签 反了，后面怎么又正常了？
		
		plt.show()
		
def counts(a,return_dict=True,one_value=False):
	
	unique, counts = numpy.unique(a, return_counts=True)	
	r= numpy.asarray((unique, counts)).T.tolist()
	if one_value and py.len(r)==1:
		return r[0][0]
	if return_dict:
		return py.dict(r)
	return r
	
def reverse_enumerate(a):
	m=a.shape[0]-1
	#(0,),v
	for n,v in py.enumerate(numpy.flip(a)):
		yield m-n,v
		
def enumerate(a,reverse=False):
	'''
0,v0 ... 9,v9
reverse:
9,v9 ... 0,v0
'''	
	if reverse:
		return reverse_enumerate(a)
	else:
		return py.enumerate(a)

def select_2d_columns(a,condition):
	''' condition: a<11
	'''
	idx=(...,*np.where((condition).all(axis=0)))
	return a[idx]
select_2d_cols=select_2d_columns

def select_2d_rows(a,condition):
	''' condition: a<11
	'''
	idx=(*np.where((condition).all(axis=1)),...)
	return a[idx]

def expand_2d_array(a,top=0,bottom=0,left=0,right=0,mode='constant',constant_values=0):
	''' only support 2d array
bottom	= 0

	'''
	return numpy.pad(a,[(top,bottom),(left,right)],mode,constant_values=constant_values)
pad=pad2d=expand_array=expand_2d_array

def pad_array(a,pad_width,mode='constant',constant_values=0):
	''' pad_width: [(d1_head,d1_tail),(d2_head,d2_tail), ...]
	'''
	return numpy.pad(a,pad_width,mode,constant_values=constant_values)

def 一维变对角矩阵(a):
	return numpy.diag(a)
diag=dj=djjz=一维变对角矩阵

def 二维变对角矩阵(a):
	return numpy.diagflat(a)

def slice_2d_array(a,x,y):
	'''不能这样用 Y.slice_2d_array(d,0:5,0:5)
SyntaxError: invalid syntax

In [629]: d[0:5,0:5]
Out[629]:
array([[0, 0, 0, 0, 0],
       [0, 1, 0, 0, 0],
       [0, 0, 2, 0, 0],
       [0, 0, 0, 3, 0],
       [0, 0, 0, 0, 4]])

In [630]: d[0:5,0:4]
Out[630]:
array([[0, 0, 0, 0],
       [0, 1, 0, 0],
       [0, 0, 2, 0],
       [0, 0, 0, 3],
       [0, 0, 0, 0]])
_.shape
 (5, 4)


'''
	return a[x,y]