Manually change xticks in matplotlib

Question

I am using the following code to make some plot of a variable having 4 values:

for station in stations:
    os.chdir(inbasedir)
    nc = Dataset(surf + station + "Fluxnet.nc", 'r+')
    soil_moist = nc.variables['SoilMoist'][:,0,0]
    plt.plot(soil_moist, c='black', linewidth=0.5, label="Soil Moisture - 4 layers")

Which gives me the following plot:

How could I modify the xticks as follow:

• how to replace the 0 by 1, the 1 by 2, the 2 by 3 and the 3 by 4?
  • how can I remove the 0.5, 1.5, 2.5 ?
  • how can I get rid of the floating point numerotation?

I tried this answer: Changing the "tick frequency" on x or y axis in matplotlib?

but it does not work and provides me the following error: TypeError: arange: scalar arguments expected instead of a tuple.

Answer 1

Make sure to plot the actual data

If 0 really denotes 1, you should plot 1 in the first place.

x = [1,2,3,4]
y = [.3,.3,.25,.29]

plt.plot(x,y)
plt.show()

Set the locations to integer numbers

from matplotlib.ticker import MultipleLocator

x = [1,2,3,4]
y = [.3,.3,.25,.29]

plt.plot(x,y)

plt.gca().xaxis.set_major_locator(MultipleLocator(1))
plt.show()

Answer 2

The xticks method of matplotlib.pyplot expects an array for the values to display as first argument and an array with labels for those elements in the first array. So add the following to your code:

plt.xticks(positions, labels)

Where positions is the array of the values you want to display, and labels the labels you want to give to those values.