setting non-basic dashes

First off, thanks for matplotlib. It really is amazing.

I can’t seem to figure out an acceptable sequence of dashes per the documentation:

‘dashes: sequence of on/off ink in points’

This is what I’m trying:`

`
mydashes = [’- ', ‘–’, '- ', ‘–’, '- ']

lines = plot(*triplets)

for i in range(len(lines)):
setp(lines[i], dashes=mydashes[i])

I’m getting errors like:

ValueError: invalid literal for float(): -

or a message about even numbers in the dash sequence being required when I don’t use even-length strings.

I really need about 5-10 different dash sequences to lines in a publication and the defaults are not quite enough.

Thanks,
John

John Prince wrote:

First off,
thanks for matplotlib. It really is amazing.

I can’t seem to figure
out an acceptable sequence of dashes per the documentation:

‘dashes: sequence of on/off ink in points’

This is what I’m trying:`

`

mydashes = [’- ',
‘–’, '- ', ‘–’, '- ']

lines =
plot(*triplets)

for i in
range(len(lines)):

  setp(lines[i],

dashes=mydashes[i])

I’m getting errors like:

ValueError: invalid
literal for float(): -

or a message about even numbers in the dash sequence being required
when I don’t use even-length strings.

I really need about 5-10 different dash sequences to lines in a
publication and the defaults are not quite enough.

Hello John,

I found this in the online documentation of the pylab.plot() function:

`The following line styles are supported:

-     : solid line

--    : dashed line

-.    : dash-dot line

:     : dotted line

.     : points

,     : pixels

o     : circle symbols

^     : triangle up symbols

v     : triangle down symbols

<     : triangle left symbols

>     : triangle right symbols

s     : square symbols

+     : plus symbols

x     : cross symbols

D     : diamond symbols

d     : thin diamond symbols

1     : tripod down symbols

2     : tripod up symbols

3     : tripod left symbols

4     : tripod right symbols

h     : hexagon symbols

H     : rotated hexagon symbols

p     : pentagon symbols

>     : vertical line symbols

_     : horizontal line symbols

steps : use gnuplot style 'steps' # kwarg only

The following color abbreviations are supported

b  : blue

g  : green

r  : red

c  : cyan

m  : magenta

y  : yellow

k  : black

w  : white

In addition, you can specify colors in many weird and

wonderful ways, including full names ‘green’, hex strings

#008000’, RGB or RGBA tuples (0,1,0,1) or grayscale

intensities as a string ‘0.8’. Of these, the string

specifications can be used in place of a fmt group, but the

tuple forms can be used only as kwargs.

Line styles and colors are combined in a single format string, as in

‘bo’ for blue circles.

The **kwargs can be used to set line properties (any property that has

a set_* method). You can use this to set a line label (for auto

legends), linewidth, anitialising, marker face color, etc. Here is an

example:

[plot](http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-plot)([1,2,3], [1,2,3], 'go-', label='line 1', linewidth=2)

[plot](http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-plot)([1,2,3], [1,4,9], 'rs',  label='line 2')

[axis](http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-axis)([0, 4, 0, 10])

[legend](http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-legend)()

HTH,

– jv

`

···

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I found this in the online documentation of the pylab.plot() function:

`The following line styles are supported:

-     : solid line

--    : dashed line

-.    : dash-dot line

:     : dotted line

.     : points

,     : pixels

o     : circle symbols

^     : triangle up symbols

v     : triangle down symbols

<     : triangle left symbols

>     : triangle right symbols

s     : square symbols

+     : plus symbols

x     : cross symbols

D     : diamond symbols

d     : thin diamond symbols

1     : tripod down symbols

2     : tripod up symbols

3     : tripod left symbols

4     : tripod right symbols

h     : hexagon symbols

H     : rotated hexagon symbols

p     : pentagon symbols

>     : vertical line symbols

_     : horizontal line symbols

steps : use gnuplot style 'steps' # kwarg only

The following color abbreviations are supported

b  : blue

g  : green

r  : red

c  : cyan

m  : magenta

y  : yellow

k  : black

w  : white

In addition, you can specify colors in many weird and

wonderful ways, including full names ‘green’, hex strings

#008000’, RGB or RGBA tuples (0,1,0,1) or grayscale

intensities as a string ‘0.8’. Of these, the string

specifications can be used in place of a fmt group, but the

tuple forms can be used only as kwargs.

Line styles and colors are combined in a single format string, as in

‘bo’ for blue circles.

The **kwargs can be used to set line properties (any property that has

a set_* method). You can use this to set a line label (for auto

legends), linewidth, anitialising, marker face color, etc. Here is an

example:

[plot](http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-plot)([1,2,3], [1,2,3], 'go-', label='line 1', linewidth=2)

[plot](http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-plot)([1,2,3], [1,4,9], 'rs',  label='line 2')

[axis](http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-axis)([0, 4, 0, 10])

[legend](http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-legend)()

HTH,

– jv

`

Thanks for the reply. Those are the formatting codes one can use by default. However, there are only 4 dash types accessible from these codes: solid, dashed, dash-dot, dotted. I think there is a way to set arbitrary dash-dot lines (say, ‘-…-…-’) using the ‘setp’ command with the ‘dashes’ argument. I just don’t know what acceptable parameters for that argument are. I’m hoping someone knows.

Thanks,
John

Use numbers:
http://matplotlib.sourceforge.net/matplotlib.lines.html

set_dashes(self, seq)
    Set the dash sequence, sequence of dashes with on off ink in
    points. If seq is empty or if seq = (None, None), the
    linestyle will be set to solid.
     
    ACCEPTS: sequence of on/off ink in points

Note: 1pt = 1/72 inch

hth,
Alan Isaac

···

On Thu, 31 Jan 2008, John Prince apparently wrote:

I think there is a way to set arbitrary
dash-dot lines