# How to invert the x or y axis

## Question:

I have a scatter plot graph with a bunch of random x, y coordinates. Currently the Y-Axis starts at 0 and goes up to the max value. I would like the Y-Axis to start at the max value and go up to 0.

```
points = [(10,5), (5,11), (24,13), (7,8)]
x_arr = []
y_arr = []
for x,y in points:
x_arr.append(x)
y_arr.append(y)
plt.scatter(x_arr,y_arr)
```

## Answers:

`axis([xmin, xmax, ymin, ymax])`

So you could add something like this at the end:

```
plt.axis([min(x_arr), max(x_arr), max(y_arr), 0])
```

Although you might want padding at each end so that the extreme points don’t sit on the border.

DisplacedAussie‘s answer is correct, but usually a shorter method is just to reverse the single axis in question:

```
plt.scatter(x_arr, y_arr)
ax = plt.gca()
ax.set_ylim(ax.get_ylim()[::-1])
```

where the `gca()`

function returns the current Axes instance and the `[::-1]`

reverses the list.

There is a new API that makes this even simpler.

```
plt.gca().invert_xaxis()
```

and/or

```
plt.gca().invert_yaxis()
```

If you’re in ipython in `pylab`

mode, then

```
plt.gca().invert_yaxis()
show()
```

the `show()`

is required to make it update the current figure.

Another similar method to those described above is to use `plt.ylim`

for example:

```
plt.ylim(max(y_array), min(y_array))
```

This method works for me when I’m attempting to compound multiple datasets on Y1 and/or Y2

Alternatively, you can use the matplotlib.pyplot.axis() function, which allows you inverting any of the plot axis

```
ax = matplotlib.pyplot.axis()
matplotlib.pyplot.axis((ax[0],ax[1],ax[3],ax[2]))
```

Or if you prefer to only reverse the X-axis, then

```
matplotlib.pyplot.axis((ax[1],ax[0],ax[2],ax[3]))
```

Indeed, you can invert both axis:

```
matplotlib.pyplot.axis((ax[1],ax[0],ax[3],ax[2]))
```

You could also use function exposed by the axes object of the scatter plot

```
scatter = plt.scatter(x, y)
ax = scatter.axes
ax.invert_xaxis()
ax.invert_yaxis()
```

If using matplotlib you can try:

matplotlib.pyplot.xlim(l, r)

matplotlib.pyplot.ylim(b, t)

These two lines set the limits of the x and y axes respectively. For the x axis, the first argument l sets the left most value, and the second argument r sets the right most value. For the y axis, the first argument b sets the bottom most value, and the second argument t sets the top most value.

if you are doing this in a subplot, here is the solution i found

```
fig, ax = plt.subplots(1,2, sharex = True)
for i in range(2):
ax[i].plot(xdata, ydata)
axs = plt.gca()
axs.invert_xaxis()
```

While using sharex, last two lines needs to be outside the for loop