Matplotlib.pyplot.flag() in Python (original) (raw)

Last Updated : 21 Apr, 2020

Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. Pyplot is a state-based interface to a Matplotlib module which provides a MATLAB-like interface.

matplotlib.pyplot.flag() Function

The flag() function in pyplot module of matplotlib library is used to set the colormap to “flag”.

Syntax: matplotlib.pyplot.flag()

Below examples illustrate the matplotlib.pyplot.flag() function in matplotlib.pyplot:

Example #1:

import matplotlib.pyplot as plt

import matplotlib.tri as tri

import numpy as np

ang = 40

rad = 10

radm = 0.35

radii = np.linspace(radm, 0.95 , rad)

angles = np.linspace( 0 , 0.5 * np.pi, ang)

angles = np.repeat(angles[..., np.newaxis],

`` rad, axis = 1 )

angles[:, 1 :: 2 ] + = np.pi / ang

x = (radii * np.cos(angles)).flatten()

y = (radii * np.sin(angles)).flatten()

z = (np.sin( 4 * radii) * np.cos( 4 * angles)).flatten()

triang = tri.Triangulation(x, y)

triang.set_mask(np.hypot(x[triang.triangles].mean(axis = 1 ),

`` y[triang.triangles].mean(axis = 1 ))

`` < radm)

tpc = plt.tripcolor(triang, z, shading = 'flat' )

plt.colorbar(tpc)

plt.flag()

plt.title( 'matplotlib.pyplot.flag() function Example\n\n' ,

`` fontweight = "bold" )

plt.show()

Output:

Example #2:

import matplotlib.pyplot as plt

import numpy as np

from matplotlib.colors import LogNorm

dx, dy = 0.015 , 0.05

x = np.arange( - 4.0 , 4.0 , dx)

y = np.arange( - 4.0 , 4.0 , dy)

X, Y = np.meshgrid(x, y)

extent = np. min (x), np. max (x), np. min (y), np. max (y)

Z1 = np.add.outer( range ( 8 ), range ( 8 )) % 2

plt.imshow(Z1, cmap = "binary_r" ,

`` interpolation = 'nearest' ,

`` extent = extent,

`` alpha = 1 )

def geeks(x, y):

`` return ( 1 - x / 2 + x * * 5 + y * * 6 ) * np.exp( - (x * * 2 + y * * 2 ))

Z2 = geeks(X, Y)

plt.imshow(Z2, alpha = 0.7 ,

`` interpolation = 'bilinear' ,

`` extent = extent)

plt.set_cmap( "gist_rainbow" )