I would like to format pi-based the y-axis which is in radians. However, when I try to test a previous solution How can I set the y axis in radians in a Python plot?, the result changes the scale making the figure shorter or making different tick values.
The original figure with the axis as float numbers is
plt.figure(figsize=(10,5))
plt.plot(t,ph,t,psi)
plt.show()
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(t,ph,t,psi)
unit = 1
y_tick = np.arange(-1, 4+unit, unit)
y_label = [r"$-\frac{\pi}{2}$", r"$0$", r"$+\frac{\pi}{2}$", r"$+\pi$", r"$+\frac{2\pi}{3}$", r"$+2\pi$"]
ax.set_yticks(y_tick*np.pi)
ax.set_yticklabels(y_label, fontsize=10)
y_label2 = [r"$" + format(r, ".2g")+ r"\pi$" for r in y_tick]
ax2 = ax.twinx()
ax2.set_yticks(y_tick*np.pi)
ax2.set_yticklabels(y_label2, fontsize=10)
plt.show()
The arrays of values of this figure are the following
ph = array([ nan, 5.15148632, 5.36208877, 5.57944677, 5.80331719,
6.03344914, 6.26958427, 0.22827168, 0.47560942, 0.72813292,
nan, nan, nan, 1.78428034, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, 5.97885977,
nan, 6.26156537, nan, 0.22449309, 0.33343571,
nan, 0.52241136, 0.60220749, 0.67207152, 0.73191573,
0.78166491, nan, 0.85064075, 0.86978065, 0.87865214,
0.87724405, 0.87865214, 0.86978065, 0.85064075, 0.82125651,
0.78166491, 0.73191573, 0.67207152, 0.60220749, 0.52241136,
nan, 0.33343571, 0.22449309, 0.10609184, 6.26156537,
6.12470264, nan, 5.82421858, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, 2.61626486,
2.33576309, 2.05832894, nan, nan, nan,
0.98555648, nan, 0.47560942, 0.22827168, 6.26958427,
6.03344914, 5.80331719, 5.57944677, 5.36208877, 5.15148632,
4.94787463, 5.15148632, 5.36208877, 5.57944677, 5.80331719,
nan, 6.26958427, 0.22827168, 0.47560942, nan,
0.98555648, nan, nan, nan, nan,
2.33576309, 2.61626486, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, 6.26156537, nan, 0.22449309, 0.33343571,
0.4327833 , 0.52241136, nan, 0.67207152, 0.73191573,
0.78166491, 0.82125651, 0.85064075, 0.86978065, 0.87865214,
0.87724405, 0.87865214, 0.86978065, 0.85064075, 0.82125651,
0.78166491, 0.73191573, 0.67207152, 0.60220749, 0.52241136,
0.4327833 , 0.33343571, 0.22449309, 0.10609184, 6.26156537,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, 2.05832894, nan, 1.51393064, 1.24758828,
nan, 0.72813292, 0.47560942, 0.22827168, 6.26958427,
6.03344914, 5.80331719, 5.57944677, 5.36208877, 5.15148632,
4.94787463, 5.15148632, 5.36208877, 5.57944677, 5.80331719,
6.03344914, 6.26958427, 0.22827168, nan, 0.72813292,
0.98555648, 1.24758828, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, 6.26156537, 0.10609184, 0.22449309, nan,
0.4327833 , 0.52241136, 0.60220749, 0.67207152, 0.73191573,
0.78166491, 0.82125651, 0.85064075, 0.86978065, 0.87865214,
0.87724405, 0.87865214, 0.86978065, 0.85064075, 0.82125651,
0.78166491, 0.73191573, 0.67207152, 0.60220749, nan,
0.4327833 , 0.33343571, 0.22449309, nan, nan,
6.12470264, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
0.98555648, 0.72813292, 0.47560942, 0.22827168, nan,
6.03344914, 5.80331719, 5.57944677, 5.36208877, 5.15148632,
4.94787463, nan, 5.36208877, 5.57944677, 5.80331719,
6.03344914, 6.26958427, nan, 0.47560942, 0.72813292,
0.98555648, 1.24758828, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, 0.22449309, 0.33343571,
0.4327833 , 0.52241136, 0.60220749, 0.67207152, 0.73191573,
0.78166491, 0.82125651, 0.85064075, 0.86978065, 0.87865214,
0.87724405, 0.87865214, 0.86978065, 0.85064075, 0.82125651,
0.78166491, 0.73191573, 0.67207152, 0.60220749, nan,
0.4327833 , nan, 0.22449309, nan, 6.26156537,
6.12470264, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, 2.61626486,
nan, 2.05832894, nan, nan, 1.24758828,
0.98555648, 0.72813292, nan, 0.22827168, 6.26958427,
6.03344914, 5.80331719, 5.57944677, 5.36208877, nan,
4.94787463, nan, 5.36208877, 5.57944677, 5.80331719,
6.03344914, 6.26958427, nan, 0.47560942, 0.72813292,
0.98555648, nan, nan, 1.78428034, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, 6.26156537, nan, nan, nan,
0.4327833 , nan, 0.60220749, 0.67207152, 0.73191573,
nan, 0.82125651, nan, 0.86978065, 0.87865214,
0.87724405, 0.87865214, 0.86978065, 0.85064075, 0.82125651,
0.78166491, nan, 0.67207152, 0.60220749, 0.52241136,
0.4327833 , 0.33343571, 0.22449309, nan, 6.26156537,
6.12470264, nan, 5.82421858, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, nan,
nan, nan, nan, nan, 2.61626486,
2.33576309, nan, 1.78428034, 1.51393064, 1.24758828,
0.98555648, 0.72813292, 0.47560942, 0.22827168, 6.26958427,
6.03344914, 5.80331719, 5.57944677, 5.36208877, 5.15148632,
4.94787463])
psi = array([-0.82595077, -0.79171153, -0.75747229, -0.72323304, -0.6889938 ,
-0.65475455, -0.62051531, -0.58627606, -0.55203682, -0.51779758,
-0.48355833, -0.44931909, -0.41507984, -0.3808406 , -0.34660135,
-0.31236211, -0.27812287, -0.24388362, -0.20964438, -0.17540513,
-0.14116589, -0.10692664, -0.0726874 , -0.03844816, -0.00420891,
0.03003033, 0.06426958, 0.09850882, 0.13274807, 0.16698731,
0.20122655, 0.2354658 , 0.26970504, 0.30394429, 0.33818353,
0.37242278, 0.40666202, 0.44090126, 0.47514051, 0.50937975,
0.543619 , 0.57785824, 0.61209749, 0.64633673, 0.68057597,
0.71481522, 0.74905446, 0.78329371, 0.81753295, 0.8517722 ,
0.88601144, 0.92025069, 0.95448993, 0.98872917, 1.02296842,
1.05720766, 1.09144691, 1.12568615, 1.1599254 , 1.19416464,
1.22840388, 1.26264313, 1.29688237, 1.33112162, 1.36536086,
1.39960011, 1.43383935, 1.46807859, 1.50231784, 1.53655708,
1.57079633, 1.53655708, 1.50231784, 1.46807859, 1.43383935,
1.39960011, 1.36536086, 1.33112162, 1.29688237, 1.26264313,
1.22840388, 1.19416464, 1.1599254 , 1.12568615, 1.09144691,
1.05720766, 1.02296842, 0.98872917, 0.95448993, 0.92025069,
0.88601144, 0.8517722 , 0.81753295, 0.78329371, 0.74905446,
0.71481522, 0.68057597, 0.64633673, 0.61209749, 0.57785824,
0.543619 , 0.50937975, 0.47514051, 0.44090126, 0.40666202,
0.37242278, 0.33818353, 0.30394429, 0.26970504, 0.2354658 ,
0.20122655, 0.16698731, 0.13274807, 0.09850882, 0.06426958,
0.03003033, -0.00420891, -0.03844816, -0.0726874 , -0.10692664,
-0.14116589, -0.17540513, -0.20964438, -0.24388362, -0.27812287,
-0.31236211, -0.34660135, -0.3808406 , -0.41507984, -0.44931909,
-0.48355833, -0.51779758, -0.55203682, -0.58627606, -0.62051531,
-0.65475455, -0.6889938 , -0.72323304, -0.75747229, -0.79171153,
-0.82595077, -0.79171153, -0.75747229, -0.72323304, -0.6889938 ,
-0.65475455, -0.62051531, -0.58627606, -0.55203682, -0.51779758,
-0.48355833, -0.44931909, -0.41507984, -0.3808406 , -0.34660135,
-0.31236211, -0.27812287, -0.24388362, -0.20964438, -0.17540513,
-0.14116589, -0.10692664, -0.0726874 , -0.03844816, -0.00420891,
0.03003033, 0.06426958, 0.09850882, 0.13274807, 0.16698731,
0.20122655, 0.2354658 , 0.26970504, 0.30394429, 0.33818353,
0.37242278, 0.40666202, 0.44090126, 0.47514051, 0.50937975,
0.543619 , 0.57785824, 0.61209749, 0.64633673, 0.68057597,
0.71481522, 0.74905446, 0.78329371, 0.81753295, 0.8517722 ,
0.88601144, 0.92025069, 0.95448993, 0.98872917, 1.02296842,
1.05720766, 1.09144691, 1.12568615, 1.1599254 , 1.19416464,
1.22840388, 1.26264313, 1.29688237, 1.33112162, 1.36536086,
1.39960011, 1.43383935, 1.46807859, 1.50231784, 1.53655708,
1.57079633, 1.53655708, 1.50231784, 1.46807859, 1.43383935,
1.39960011, 1.36536086, 1.33112162, 1.29688237, 1.26264313,
1.22840388, 1.19416464, 1.1599254 , 1.12568615, 1.09144691,
1.05720766, 1.02296842, 0.98872917, 0.95448993, 0.92025069,
0.88601144, 0.8517722 , 0.81753295, 0.78329371, 0.74905446,
0.71481522, 0.68057597, 0.64633673, 0.61209749, 0.57785824,
0.543619 , 0.50937975, 0.47514051, 0.44090126, 0.40666202,
0.37242278, 0.33818353, 0.30394429, 0.26970504, 0.2354658 ,
0.20122655, 0.16698731, 0.13274807, 0.09850882, 0.06426958,
0.03003033, -0.00420891, -0.03844816, -0.0726874 , -0.10692664,
-0.14116589, -0.17540513, -0.20964438, -0.24388362, -0.27812287,
-0.31236211, -0.34660135, -0.3808406 , -0.41507984, -0.44931909,
-0.48355833, -0.51779758, -0.55203682, -0.58627606, -0.62051531,
-0.65475455, -0.6889938 , -0.72323304, -0.75747229, -0.79171153,
-0.82595077, -0.79171153, -0.75747229, -0.72323304, -0.6889938 ,
-0.65475455, -0.62051531, -0.58627606, -0.55203682, -0.51779758,
-0.48355833, -0.44931909, -0.41507984, -0.3808406 , -0.34660135,
-0.31236211, -0.27812287, -0.24388362, -0.20964438, -0.17540513,
-0.14116589, -0.10692664, -0.0726874 , -0.03844816, -0.00420891,
0.03003033, 0.06426958, 0.09850882, 0.13274807, 0.16698731,
0.20122655, 0.2354658 , 0.26970504, 0.30394429, 0.33818353,
0.37242278, 0.40666202, 0.44090126, 0.47514051, 0.50937975,
0.543619 , 0.57785824, 0.61209749, 0.64633673, 0.68057597,
0.71481522, 0.74905446, 0.78329371, 0.81753295, 0.8517722 ,
0.88601144, 0.92025069, 0.95448993, 0.98872917, 1.02296842,
1.05720766, 1.09144691, 1.12568615, 1.1599254 , 1.19416464,
1.22840388, 1.26264313, 1.29688237, 1.33112162, 1.36536086,
1.39960011, 1.43383935, 1.46807859, 1.50231784, 1.53655708,
1.57079633, 1.53655708, 1.50231784, 1.46807859, 1.43383935,
1.39960011, 1.36536086, 1.33112162, 1.29688237, 1.26264313,
1.22840388, 1.19416464, 1.1599254 , 1.12568615, 1.09144691,
1.05720766, 1.02296842, 0.98872917, 0.95448993, 0.92025069,
0.88601144, 0.8517722 , 0.81753295, 0.78329371, 0.74905446,
0.71481522, 0.68057597, 0.64633673, 0.61209749, 0.57785824,
0.543619 , 0.50937975, 0.47514051, 0.44090126, 0.40666202,
0.37242278, 0.33818353, 0.30394429, 0.26970504, 0.2354658 ,
0.20122655, 0.16698731, 0.13274807, 0.09850882, 0.06426958,
0.03003033, -0.00420891, -0.03844816, -0.0726874 , -0.10692664,
-0.14116589, -0.17540513, -0.20964438, -0.24388362, -0.27812287,
-0.31236211, -0.34660135, -0.3808406 , -0.41507984, -0.44931909,
-0.48355833, -0.51779758, -0.55203682, -0.58627606, -0.62051531,
-0.65475455, -0.6889938 , -0.72323304, -0.75747229, -0.79171153,
-0.82595077, -0.79171153, -0.75747229, -0.72323304, -0.6889938 ,
-0.65475455, -0.62051531, -0.58627606, -0.55203682, -0.51779758,
-0.48355833, -0.44931909, -0.41507984, -0.3808406 , -0.34660135,
-0.31236211, -0.27812287, -0.24388362, -0.20964438, -0.17540513,
-0.14116589, -0.10692664, -0.0726874 , -0.03844816, -0.00420891,
0.03003033, 0.06426958, 0.09850882, 0.13274807, 0.16698731,
0.20122655, 0.2354658 , 0.26970504, 0.30394429, 0.33818353,
0.37242278, 0.40666202, 0.44090126, 0.47514051, 0.50937975,
0.543619 , 0.57785824, 0.61209749, 0.64633673, 0.68057597,
0.71481522, 0.74905446, 0.78329371, 0.81753295, 0.8517722 ,
0.88601144, 0.92025069, 0.95448993, 0.98872917, 1.02296842,
1.05720766, 1.09144691, 1.12568615, 1.1599254 , 1.19416464,
1.22840388, 1.26264313, 1.29688237, 1.33112162, 1.36536086,
1.39960011, 1.43383935, 1.46807859, 1.50231784, 1.53655708,
1.57079633, 1.53655708, 1.50231784, 1.46807859, 1.43383935,
1.39960011, 1.36536086, 1.33112162, 1.29688237, 1.26264313,
1.22840388, 1.19416464, 1.1599254 , 1.12568615, 1.09144691,
1.05720766, 1.02296842, 0.98872917, 0.95448993, 0.92025069,
0.88601144, 0.8517722 , 0.81753295, 0.78329371, 0.74905446,
0.71481522, 0.68057597, 0.64633673, 0.61209749, 0.57785824,
0.543619 , 0.50937975, 0.47514051, 0.44090126, 0.40666202,
0.37242278, 0.33818353, 0.30394429, 0.26970504, 0.2354658 ,
0.20122655, 0.16698731, 0.13274807, 0.09850882, 0.06426958,
0.03003033, -0.00420891, -0.03844816, -0.0726874 , -0.10692664,
-0.14116589, -0.17540513, -0.20964438, -0.24388362, -0.27812287,
-0.31236211, -0.34660135, -0.3808406 , -0.41507984, -0.44931909,
-0.48355833, -0.51779758, -0.55203682, -0.58627606, -0.62051531,
-0.65475455, -0.6889938 , -0.72323304, -0.75747229, -0.79171153,
-0.82595077, -0.79171153, -0.75747229, -0.72323304, -0.6889938 ,
-0.65475455, -0.62051531, -0.58627606, -0.55203682, -0.51779758,
-0.48355833, -0.44931909, -0.41507984, -0.3808406 , -0.34660135,
-0.31236211, -0.27812287, -0.24388362, -0.20964438, -0.17540513,
-0.14116589, -0.10692664, -0.0726874 , -0.03844816, -0.00420891,
0.03003033, 0.06426958, 0.09850882, 0.13274807, 0.16698731,
0.20122655, 0.2354658 , 0.26970504, 0.30394429, 0.33818353,
0.37242278, 0.40666202, 0.44090126, 0.47514051, 0.50937975,
0.543619 , 0.57785824, 0.61209749, 0.64633673, 0.68057597,
0.71481522, 0.74905446, 0.78329371, 0.81753295, 0.8517722 ,
0.88601144, 0.92025069, 0.95448993, 0.98872917, 1.02296842,
1.05720766, 1.09144691, 1.12568615, 1.1599254 , 1.19416464,
1.22840388, 1.26264313, 1.29688237, 1.33112162, 1.36536086,
1.39960011, 1.43383935, 1.46807859, 1.50231784, 1.53655708,
1.57079633, 1.53655708, 1.50231784, 1.46807859, 1.43383935,
1.39960011, 1.36536086, 1.33112162, 1.29688237, 1.26264313,
1.22840388, 1.19416464, 1.1599254 , 1.12568615, 1.09144691,
1.05720766, 1.02296842, 0.98872917, 0.95448993, 0.92025069,
0.88601144, 0.8517722 , 0.81753295, 0.78329371, 0.74905446,
0.71481522, 0.68057597, 0.64633673, 0.61209749, 0.57785824,
0.543619 , 0.50937975, 0.47514051, 0.44090126, 0.40666202,
0.37242278, 0.33818353, 0.30394429, 0.26970504, 0.2354658 ,
0.20122655, 0.16698731, 0.13274807, 0.09850882, 0.06426958,
0.03003033, -0.00420891, -0.03844816, -0.0726874 , -0.10692664,
-0.14116589, -0.17540513, -0.20964438, -0.24388362, -0.27812287,
-0.31236211, -0.34660135, -0.3808406 , -0.41507984, -0.44931909,
-0.48355833, -0.51779758, -0.55203682, -0.58627606, -0.62051531,
-0.65475455, -0.6889938 , -0.72323304, -0.75747229, -0.79171153,
-0.82595077])
and
t = np.arange(0, 20 + 1/35, 1/35)
