Axes.errorbar(x, y, yerr=None, xerr=None, fmt='', ecolor=None, elinewidth=None, capsize=None, barsabove=False, lolims=False, uplims=False, xlolims=False, xuplims=False, errorevery=1, capthick=None, *, data=None, **kwargs)[source]

Plot y versus x as lines and/or markers with attached errorbars.

x, y define the data locations, xerr, yerr define the errorbar sizes. By default, this draws the data markers/lines as well the errorbars. Use fmt='none' to draw errorbars without any data markers.

x, yfloat or array-like

The data positions.

xerr, yerrfloat or array-like, shape(N,) or shape(2, N), optional

The errorbar sizes:

  • scalar: Symmetric +/- values for all data points.
  • shape(N,): Symmetric +/-values for each data point.
  • shape(2, N): Separate - and + values for each bar. First row contains the lower errors, the second row contains the upper errors.
  • None: No errorbar.

Note that all error arrays should have positive values.

See Different ways of specifying error bars for an example on the usage of xerr and yerr.

fmtstr, default: ''

The format for the data points / data lines. See plot for details.

Use 'none' (case insensitive) to plot errorbars without any data markers.

ecolorcolor, default: None

The color of the errorbar lines. If None, use the color of the line connecting the markers.

elinewidthfloat, default: None

The linewidth of the errorbar lines. If None, the linewidth of the current style is used.

capsizefloat, default: rcParams["errorbar.capsize"] (default: 0.0)

The length of the error bar caps in points.

capthickfloat, default: None

An alias to the keyword argument markeredgewidth (a.k.a. mew). This setting is a more sensible name for the property that controls the thickness of the error bar cap in points. For backwards compatibility, if mew or markeredgewidth are given, then they will over-ride capthick. This may change in future releases.

barsabovebool, default: False

If True, will plot the errorbars above the plot symbols. Default is below.

lolims, uplims, xlolims, xuplimsbool, default: False

These arguments can be used to indicate that a value gives only upper/lower limits. In that case a caret symbol is used to indicate this. lims-arguments may be scalars, or array-likes of the same length as xerr and yerr. To use limits with inverted axes, set_xlim or set_ylim must be called before errorbar(). Note the tricky parameter names: setting e.g. lolims to True means that the y-value is a lower limit of the True value, so, only an upward-pointing arrow will be drawn!

erroreveryint or (int, int), default: 1

draws error bars on a subset of the data. errorevery =N draws error bars on the points (x[::N], y[::N]). errorevery =(start, N) draws error bars on the points (x[start::N], y[start::N]). e.g. errorevery=(6, 3) adds error bars to the data at (x[6], x[9], x[12], x[15], ...). Used to avoid overlapping error bars when two series share x-axis values.


The container contains:

  • plotline: Line2D instance of x, y plot markers and/or line.
  • caplines: A tuple of Line2D instances of the error bar caps.
  • barlinecols: A tuple of LineCollection with the horizontal and vertical error ranges.
Other Parameters:

All other keyword arguments are passed on to the plot call drawing the markers. For example, this code makes big red squares with thick green edges:

x, y, yerr = rand(3, 10)
errorbar(x, y, yerr, marker='s', mfc='red',
         mec='green', ms=20, mew=4)

where mfc, mec, ms and mew are aliases for the longer property names, markerfacecolor, markeredgecolor, markersize and markeredgewidth.

Valid kwargs for the marker properties are Line2D properties:

Property Description
agg_filter a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array
alpha float or None
animated bool
antialiased or aa bool
clip_box Bbox
clip_on bool
clip_path Patch or (Path, Transform) or None
color or c color
contains unknown
dash_capstyle {'butt', 'round', 'projecting'}
dash_joinstyle {'miter', 'round', 'bevel'}
dashes sequence of floats (on/off ink in points) or (None, None)
data (2, N) array or two 1D arrays
drawstyle or ds {'default', 'steps', 'steps-pre', 'steps-mid', 'steps-post'}, default: 'default'
figure Figure
fillstyle {'full', 'left', 'right', 'bottom', 'top', 'none'}
gid str
in_layout bool
label object
linestyle or ls {'-', '--', '-.', ':', '', (offset, on-off-seq), ...}
linewidth or lw float
marker marker style string, Path or MarkerStyle
markeredgecolor or mec color
markeredgewidth or mew float
markerfacecolor or mfc color
markerfacecoloralt or mfcalt color
markersize or ms float
markevery None or int or (int, int) or slice or List[int] or float or (float, float) or List[bool]
path_effects AbstractPathEffect
picker unknown
pickradius float
rasterized bool or None
sketch_params (scale: float, length: float, randomness: float)
snap bool or None
solid_capstyle {'butt', 'round', 'projecting'}
solid_joinstyle {'miter', 'round', 'bevel'}
transform matplotlib.transforms.Transform
url str
visible bool
xdata 1D array
ydata 1D array
zorder float



In addition to the above described arguments, this function can take a data keyword argument. If such a data argument is given, the following arguments can also be string s, which is interpreted as data[s] (unless this raises an exception): x, y, xerr, yerr.

Objects passed as data must support item access (data[s]) and membership test (s in data).