I'm trying to add some axis-labels to a graph which contains the Greek letter 'rho'. To do this I want to use the LaTeX capability of Matplotlib but it seems to have a problem with the \rho symbol.
Here is a minimal example:
import matplotlib.pyplot as plt
from matplotlib import rc,rcParams
rc('text',usetex=True)
rcParams.update({'font.size': 16})
plt.plot([0,1,2,3,4],[0,1,4,9,16])
plt.xlabel('\rho A_i') # works if \rho is replaced with, for example, \sigma
plt.ylabel('Something else')
plt.show()
Upon running the first time I get a bunch of LaTeX errors and a blank figure window, running again shows the graph but the xlabel reads 'ho Ai ' where the i is subscript as expected.
The weird thing is if I replace \rho with something else, say, \sigma it shows up correctly. Can anybody tell me why it is not happy with my code example and how to fix it?
Thanks.
P.s. I tried putting the expression in $..$ but that changed nothing.
I think you are supposed to use raw strings, and use the $ signs as well. Try:
plt.xlabel(r'$\rho A_i$')
Be careful when you're using \n , \r and so on in a string. Those are commands for e.g. entering a new line etc.
https://docs.python.org/2/library/re.html
To make sure you don't use these regular expression operators put \\rho instead of \rho.
Related
So here is an example of a multiline string in vscode/python:
Cursor is after the p , and then you press enter, and end up like this:
i.e. the string ends up indented, which seems what you almost never want - why have an arbitratly amount of whitespace on the next line of this string ?
Is there any way change this in vscode, i.e. for multiline strings, it should end up with this:
I think this problem is related to different coding styles of different people.
For example,
def example(x):
if x:
a = '''
This is help
'''
def example(x):
if x:
a = '''This is help
'''
The automatic indenting of vscode line breaks is based on code blocks. If you want Vscode can identify multiline string, I think it would be better to submit future request in github. I've submitted this issue for you.
I am not 100% sure if what OP meant is just to refer to the indentation in the editor (namely, VSC) or if, by this:
i.e. the string ends up indented, which seems what you almost never want - why have an arbitrary amount of white space on the next line of this string?
...they also meant to refer to the actual output of the multi-line string,
(or also, just in case anybody else finds this post looking for a way to avoid this affecting the actual output of the multi-line string), I'd like to add as a complementary answer (cannot comment yet) that this was already beautifully answered here.
If that's the case and you're reading this for that reason, in short, all you want is to import the standard lib 'inspect' and post-process your string with it, using the cleandoc method.
Without breaking the indentation in your IDE, this method makes sure to give you the string output you actually expected:
All leading whitespace is removed from the first line. Any leading whitespace that can be uniformly removed from the second line onwards is removed. Empty lines at the beginning and end are subsequently removed. Also, all tabs are expanded to spaces.
(From the docs link above)
Hope that helps anyone.
I have a script that processes the output of a command (the aws help cli command).
I step through the output line-by-line and don't start the actual real parsing until I encounter the text "AVAILABLE COMMANDS" at which point I set a flag to true and start further processing on each line.
I've had this working fine - BUT on Ubuntu we encounter a problem which is this :
The CLI highlights the text in a way I have not seen before:
The output is very long, so I've grep'd the particular line in question - see below:
># aws ec2 help | egrep '^A'
>AVAILABLE COMMANDS
># aws ec2 help | egrep '^A' | cat -vet
>A^HAV^HVA^HAI^HIL^HLA^HAB^HBL^HLE^HE C^HCO^HOM^HMM^HMA^HAN^HND^HDS^HS$
What I haven't seen before is that each letter that is highligted is in the format X^HX.
I'd like to apply a simple transformation of the type X^HX --> X (for all a-zA-Z).
What have I tried so far:
well my workaround is this - first I remove control characters like this:
String = re.sub(r'[\x00-\x1f\x7f-\x9f]','',String)
but I still have to search for 'AAVVAAIILLAABBLLEE' which is totally ugly. I considered using a further regex to turn doubles to singles but that will catch true doubles and get messy.
I started writing a function with an iteration across a constructed list of alpha characters to translate as described, and I used hexdump to try to figure out the exact \x code of the control characters in question but could not get it working - I could remove H but not the ^.
I really don't want to use any additional modules because I want to make this available to people without them having to install extras. In conclusion I have a workaround that is quite ugly, but I'm sure someone must know a quick an easy way to do this translation. It's odd that it only seems to show up on Ubuntu.
After looking at this a little further I was able to put in place a solution:
from string import ascii_lowercase
from string import ascii_uppercase
def RemoveUbuntuHighlighting(String):
for Char in ascii_uppercase + ascii_lowercase:
Match = Char + '\x08' + Char
String = re.sub(Match,Char,String)
return(String)
I'm still a little confounded to see characters highlighted in the format (X\x08X), the arrangement does seem to repeat the same information unnecessarily.
The other thing I would advise to anyone not familiar with reading hexcode is that each pair of hexes is swapped around with respect to the order of their appearance.
A much simpler and more reliable fix is to replace a backspace and duplicate of any character.
I have also augmented this to handle underscores using the same mechanism (character, backspace, underscore).
String = re.sub(r'(.)\x08(\1|_)', r'\1', String)
Demo: https://ideone.com/yzwd2V
This highlighting was standard back when output was to a line printer; backspacing and printing the same character again would add pigmentation to produce boldface. (Backspacing and printing an underscore would produce underlining.)
Probably the AWS CLI can be configured to disable this by setting the TERM variable to something like dumb. There is also a utility col which can remove this formatting (try col-b; maybe see also colcrt). Though perhaps really the best solution would be to import the AWS Python code and extract the help message natively.
Unfortunately due to a problem with windows I cannot render any of my matplotlib text with LaTeX. So basically I need away already in matplotlib's text handling to place a line underneath a letter.
So far the closest I have is ax.text(x,y,z, r'$\mathbf{\underbar r}$'), but this just produces _r. So if there is a way to get this bar under the 'r' that would be amazing. Thanks in advance!
P.S. I have already tried ax.text(x,y,z, r'$\underline{\mathbf{r}}$') but this doesn't seem to work, :,(
Edit
Just realized that you can 'cheat' matplotlib :D by placing text in the exact same position with just an \underbar, which makes it appear under the letter. i.e. ax.text(x,y,z, r'$\mathbf{r}$') followed by ax.text(x,y,z, r'$\mathbf{\underbar}$')
But a quicker way would still be appreciated, thanks!
You could use some negative spacing between the underbar and your character. In this case it seems that tripling the \! works well:
ax.text(2,7, r'$\mathbf{\underbar \!\!\! r }$')
I have seen this issue pop up here and there but have yet to find a suitable answer.
When making a plot in matplotlib, the only way to insert symbols and math functions (like fractions, exponents, etc...) is to use TeX formatting. However, by default TeX formatting uses a different font AND italicizes the text. So for example, if I wanted an axis label to say the following:
photons/cm^2/s/Angstrom
I have to do the following:
ax1.set_ylabel(r'Photons/$cm^2$/s/$\AA$')
This produces a very ugly label that uses 2 different fonts and has bits and pieces italicized.
How do I permanently change the font of TeX (Not the other way around) so that it matches the default font used by matplotlib?
I have seen other solutions that tell the user to manually make all text the same in a plot by using \mathrm{} for example but this is ridiculously tedious. I have also seen solutions which change the default font of matplotlib to match TeX which seem utterly backwards to me.
It turns out the solution was rather simple and a colleague of mine had the solution.
If I were to use this line of code to create a title:
fig.suptitle(r'$H_2$ Emission from GJ832')
The result would be "H2 Emission from GJ832" which is an illustration of the problem I was having. However, it turns out anything inside of the $$ is converted to math type and thus the italics assigned.
If we change that line of code to the following:
fig.suptitle(r'H$_2$ Emission from GJ832')
Then the result is "H2 Emission from GJ832" without the italics. So this is an example of where we can constrain the math type to include only the math parts of the text, namely creating the subscript of 2.
However, if I were to change the code to the following:
fig.suptitle(r'H$_{two}$ Emission from GJ832')
the result would be "Htwo Emission from GJ832" which introduces the italics again. In this case, and for any case where you must have text (or are creating unit symbols) inside the dollar signs, you can easily remove the italics the following way:
fig.suptitle(r'H$_{\rm two}$ Emission from GJ832')
or in the case of creating a symbol:
ax2.set_xlabel(r'Wavelength ($\rm \AA$)')
The former results in "Htwo Emission from GJ832"
and the latter in "Wavelength (A)"
where A is the Angstrom symbol.
Both of these produce the desired result with nothing italicized by calling \rm before the text or symbol in the dollar signs. The result is nothing italicized INCLUDING the Angstrom symbol created by \AA.
While this doesn't change the default of the TeX formatting, it IS a simple solution to the problem and doesn't require any new packages. Thank you Roland Smith for the suggestions anyway. I hope this helps others who have been struggling with the same issue.
For typesetting units, use the siunitx package (with mode=text) rather than math mode.
Update: The above is only valid when you have defined text.usetex : True in your rc settings.
From the matplotlib docs:
Note that you do not need to have TeX installed, since matplotlib ships its own TeX expression parser, layout engine and fonts.
And:
Regular text and mathtext can be interleaved within the same string. Mathtext can use the Computer Modern fonts (from (La)TeX), STIX fonts (with are designed to blend well with Times) or a Unicode font that you provide. The mathtext font can be selected with the customization variable mathtext.fontset
Reading this, it sounds that setting mathtext.fontset and the regular font that matplotlib uses the same would solve the problem if you don't use TeX.
I'm using matplotlib to produce some graphics, and I'm using latex for the legends.
More specifically, I'm trying to use something like this:
loglog(x,x, '-r',label='$ \alpha $')
legend()
show()
However, this code does not present a legend on the figure, and gets error after I close the image.
I'm using the enthought package (for mac), but the error comes from the pylab/scipy.
The error the appears is exactly:
$ lpha $ (at char 0), (line:1, col:1)
However, if use the \mu or \gamma, it works well!! I only found about this problem on \beta and \alpha.
Does anyone knows what this can be? I believe python is interpreting "\a" as some character... but I don't know how should I debug / avoid it.
The issue is that \a and \b have special meaning inside a Python string literal.
I recommend that you use raw strings whenever there is a backslash embedded inside a string:
r'$ \alpha $'
In addition to using raw strings (as mentioned in the post above) you can also escape the backslash. So typing \\alpha and \\beta will also work.
Hi if your \alpha and \beta don't work on Latex
use $\alpha$
likewise $\beta$ so on.
hope it works