Related
I use makie.jl with slicesNumb for visualization of PET/CT scans, I have 3d array of attenuation values and I display heatmap with changing slices using slider - this works well I have two problems
I do not know how to be able to define custom colormaps (basically I need to be able to specify that all above some threshold value will be black and all below white and values between will have grey values proportional to attenuation value).
2)I would like to be able to display to display over my image (tachnically heatmap) another ones where I would be able to controll transparency - alpha value of pixels - in order to display some annotations/ PET ...
code that works but without those 2 functionalities and how it looks
using GLMakie
```#doc
simple display of single image - only in transverse plane
```
function singleCtScanDisplay(arr ::Array{Number, 3})
fig = Figure()
sl_x = Slider(fig[2, 1], range = 1:1:size(arr)[3], startvalue = 40)
ax = Axis(fig[1, 1])
hm = heatmap!(ax, lift(idx-> arr[:,:, floor(idx)], sl_x.value) ,colormap = :grays)
Colorbar(fig[1, 2], hm)
fig
end
Thanks for help !
You can use Colors and ColorSchemeTools, but you will need to add the top and bottom of the scheme according to your thresholds.
using Colors, ColorSchemeTools
truemin = 0
truemax = 600
max_shown_black = 20
min_shown_white = 500
data = rand(truemin:truemax, (500, 500, 20))
grayscheme = [fill(colorant"black", max_shown_black - truemin + 1);
collect(make_colorscheme(identity, identity, identity,
length = min_shown_white - max_shown_black - 1));
fill(colorant"white", truemax - min_shown_white + 1)]
For controlling alpha, I would add a popup window with an alpha slider. Take a look at some of the distributable DICOM tools for examples.
I finally managed it basically I load 3 dimensional data stored in hdf5 (I loaded it into hdf5 from raw using python)
It enables viewing transverse slices and annotate 3d pathes in a mask that will be displayed over main image
exmpleH = #spawnat persistenceWorker Main.h5manag.getExample()
minimumm = -1000
maximumm = 2000
arrr= fetch(exmpleH)
imageDim = size(arrr)
using GLMakie
maskArr = Observable(BitArray(undef, imageDim))
MyImgeViewer.singleCtScanDisplay(arrr, maskArr,minimumm, maximumm)
Now definition of the required modules
```#doc
functions responsible for displaying medical image Data
```
using DrWatson
#quickactivate "Probabilistic medical segmentation"
module MyImgeViewer
using GLMakie
using Makie
#using GeometryBasics
using GeometricalPredicates
using ColorTypes
using Distributed
using GLMakie
using Main.imageViewerHelper
using Main.workerNumbers
## getting id of workers
```#doc
simple display of single image - only in transverse plane we are adding also a mask that
arrr - main 3 dimensional data representing medical image for example in case of CT each voxel represents value of X ray attenuation
minimumm, maximumm - approximately minimum and maximum values we can have in our image
```
function singleCtScanDisplay(arrr ::Array{Number, 3}, maskArr , minimumm, maximumm)
#we modify 2 pixels just in order to make the color range constant so slices will be displayed in the same windows
arrr[1,1,:].= minimumm
arrr[2,1,:].= maximumm
imageDim = size(arrr) # dimenstion of the primary image for example CT scan
slicesNumb =imageDim[3] # number of slices
#defining layout variables
scene, layout = GLMakie.layoutscene(resolution = (600, 400))
ax1 = layout[1, 1] = GLMakie.Axis(scene, backgroundcolor = :transparent)
ax2 = layout[1, 1] = GLMakie.Axis(scene, backgroundcolor = :transparent)
#control widgets
sl_x =layout[2, 1]= GLMakie.Slider(scene, range = 1:1: slicesNumb , startvalue = slicesNumb/2 )
sliderXVal = sl_x.value
#color maps
cmwhite = cgrad(range(RGBA(10,10,10,0.01), stop=RGBA(0,0,255,0.4), length=10000));
greyss = createMedicalImageColorSchemeB(200,-200,maximumm, minimumm )
####heatmaps
#main heatmap that holds for example Ct scan
currentSliceMain = GLMakie.#lift(arrr[:,:, convert(Int32,$sliderXVal)])
hm = GLMakie.heatmap!(ax1, currentSliceMain ,colormap = greyss)
#helper heatmap designed to respond to both changes in slider and changes in the bit matrix
currentSliceMask = GLMakie.#lift($maskArr[:,:, convert(Int32,$sliderXVal)])
hmB = GLMakie.heatmap!(ax1, currentSliceMask ,colormap = cmwhite)
#adding ability to be able to add information to mask where we clicked so in casse of mit matrix we will set the point where we clicked to 1
indicatorC(ax1,imageDim,scene,maskArr,sliderXVal)
#displaying
colorB = layout[1,2]= Colorbar(scene, hm)
GLMakie.translate!(hmB, Vec3f0(0,0,5))
scene
end
```#doc
inspired by https://github.com/JuliaPlots/Makie.jl/issues/810
Generaly thanks to this function the viewer is able to respond to clicking on the slices and records it in the supplied 3 dimensional AbstractArray
ax - Axis which store our heatmap slices which we want to observe wheather user clicked on them and where
dims - dimensions of main image for example CT
sc - Scene where our axis is
maskArr - the 3 dimensional bit array that has exactly the same dimensions as main Array storing image
sliceNumb - represents on what slide we are on currently on - ussually it just give information from slider
```
function indicatorC(ax::Axis,dims::Tuple{Int64, Int64, Int64},sc::Scene,maskArr,sliceNumb::Observable{Any})
register_interaction!(ax, :indicator) do event::GLMakie.MouseEvent, axis
if event.type === MouseEventTypes.leftclick
println("clicked")
##async begin
#appropriately modyfing wanted pixels in mask array
#async calculateMouseAndSetmaskWrap(maskArr, event,sc,dims,sliceNumb)
#
#
# println("fetched" + fetch(maskA))
# finalize(maskA)
#end
return true
#print("xMouse: $(xMouse) yMouse: $(yMouse) compBoxWidth: $(compBoxWidth) compBoxHeight: $(compBoxHeight) calculatedXpixel: $(calculatedXpixel) calculatedYpixel: $(calculatedYpixel) pixelsNumbInX $(pixelsNumbInX) ")
end
end
end
```#doc
wrapper for calculateMouseAndSetmask - from imageViewerHelper module
given mouse event modifies mask accordingly
maskArr - the 3 dimensional bit array that has exactly the same dimensions as main Array storing image
event - mouse event passed from Makie
sc - scene we are using in Makie
```
function calculateMouseAndSetmaskWrap(maskArr, event,sc,dims,sliceNumb)
maskArr[] = calculateMouseAndSetmask(maskArr, event,sc,dims,sliceNumb)
end
end #module
and helper methods
```#doc
functions responsible for helping in image viewer - those functions are meant to be invoked on separate process
- in parallel
```
using DrWatson
#quickactivate "Probabilistic medical segmentation"
module imageViewerHelper
using Documenter
using ColorTypes
using Colors, ColorSchemeTools
using Makie
export calculateMouseAndSetmask
export createMedicalImageColorSchemeB
# using AbstractPlotting
```#doc
given mouse event modifies mask accordingly
maskArr - the 3 dimensional bit array that has exactly the same dimensions as main Array storing image
event - mouse event passed from Makie
sc - scene we are using in Makie
```
function calculateMouseAndSetmask(maskArr, event,sc,dims,sliceNumb)
#position from top left corner
xMouse= Makie.to_world(sc,event.data)[1]
yMouse= Makie.to_world(sc,event.data)[2]
#data about height and width in layout
compBoxWidth = 510
compBoxHeight = 510
#image dimensions - number of pixels from medical image for example ct scan
pixelsNumbInX =dims[1]
pixelsNumbInY =dims[2]
#calculating over which image pixel we are
calculatedXpixel =convert(Int32, round( (xMouse/compBoxWidth)*pixelsNumbInX) )
calculatedYpixel = convert(Int32,round( (yMouse/compBoxHeight)*pixelsNumbInY ))
sliceNumbConv =convert(Int32,round( sliceNumb[] ))
#appropriately modyfing wanted pixels in mask array
return markMaskArrayPatch( maskArr ,CartesianIndex(calculatedXpixel, calculatedYpixel, sliceNumbConv ),2)
end
```#doc
maskArr - the 3 dimensional bit array that has exactly the same dimensions as main Array storing image
point - cartesian coordinates of point around which we want to modify the 3 dimensional array from 0 to 1
```
function markMaskArrayPatch(maskArr, pointCart::CartesianIndex{3}, patchSize ::Int64)
ones = CartesianIndex(patchSize,patchSize,patchSize) # cartesian 3 dimensional index used for calculations to get range of the cartesian indicis to analyze
maskArrB = maskArr[]
for J in (pointCart-ones):(pointCart+ones)
diff = J - pointCart # diffrence between dimensions relative to point of origin
if cartesianTolinear(diff) <= patchSize
maskArrB[J]=1
end
end
return maskArrB
end
```#doc
works only for 3d cartesian coordinates
cart - cartesian coordinates of point where we will add the dimensions ...
```
function cartesianTolinear(pointCart::CartesianIndex{3}) :: Int16
abs(pointCart[1])+ abs(pointCart[2])+abs(pointCart[3])
end
```#doc
creating grey scheme colors for proper display of medical image mainly CT scan
min_shown_white - max_shown_black range over which the gradint of greys will be shown
truemax - truemin the range of values in the image for which we are creating the scale
```
#taken from https://stackoverflow.com/questions/67727977/how-to-create-julia-color-scheme-for-displaying-ct-scan-makie-jl/67756158#67756158
function createMedicalImageColorSchemeB(min_shown_white,max_shown_black,truemax,truemin ) ::Vector{Any}
# println("max_shown_black - truemin + 1")
# println(max_shown_black - truemin + 1)
# println(" min_shown_white - max_shown_black - 1")
# println( min_shown_white - max_shown_black - 1)
# println("truemax - min_shown_white + 1")
# println(truemax - min_shown_white + 1)
return [fill(colorant"black", max_shown_black - truemin + 1);
collect(make_colorscheme(identity, identity, identity,
length = min_shown_white - max_shown_black - 1));
fill(colorant"white", truemax - min_shown_white + 1)]
end
end #module
Say I have a line coor1: (0,300) coor2: (600,300)
With that, I want to find the 2 middle third points which would be (200,300) (400,300)
Normally, I'd do something like:
x = (xCoor2 - xCoor1) * (1.0/3.0) + xCoor1;
y = yCoor1 - (yCoor1 - yCoor2) * (1.0/3.0);
But that would only work successfully in some cases. I need one statement that can find those 2 points when coor1 and coor2 are anywhere. Such as coor1: (400,400) coor2: (600,600)
Point left{0.0,300.0}, right{600.0,300.0}, one_third, two_thirds;
one_third = left + (right - left) *1.0/3.0;
two_thirds= left + (right - left) *2.0/3.0;
or more explicitly
one_third.x = left.x + (right.x - left.x) *1.0/3.0;
one_third.y = left.y + (right.y - left.y) *1.0/3.0;
two_thirds.x= left.x + (right.x - left.x) *2.0/3.0;
two_thirds.y= left.y + (right.y - left.y) *2.0/3.0;
I'm trying to do something that I'd normally consider trivial but seems to be very difficult in bokeh: Adding a vertical colorbar to a plot and then having the title of the colorbar (a.k.a. the variable behind the colormapping) appear to one side of the colorbar but rotated 90 degrees clockwise from horizontal.
From what I can tell of the bokeh ColorBar() interface (looking at both documentation and using the python interpreter's help() function for this element), this is not possible. In desperation I have added my own Label()-based annotation. This works but is klunky and displays odd behavior when deployed in a bokeh serve situation--that the width of the data window on the plot varies inversely with the length of the title colorbar's title string.
Below I've included a modified version of the bokeh server mpg example. Apologies for its complexity, but I felt this was the best way to illustrate the problem using infrastructure/data that ships with bokeh. For those unfamiliar with bokeh serve, this code snippet needs to saved to a file named main.py that resides in a directory--for the sake of argument let's say CrossFilter2--and in the parent directory of CrossFilter2 one needs to invoke the command
bokeh serve --show CrossFilter2
this will then display in a browser window (localhost:5006/CrossFilter2) and if you play with the color selection widget you will see what I mean, namely that short variable names such as 'hp' or 'mpg' result in a wider data display windows than longer variable names such as 'accel' or 'weight'. I suspect that there may be a bug in how label elements are sized--that their x and y dimensions are swapped--and that bokeh has not understood that the label element has been rotated.
My questions are:
Must I really have to go to this kind of trouble to get a simple colorbar label feature that I can get with little-to-no trouble in matplotlib/plotly?
If I must go through the hassle you can see in my sample code, is there some other way I can do this that avoids the data window width problem?
import numpy as np
import pandas as pd
from bokeh.layouts import row, widgetbox
from bokeh.models import Select
from bokeh.models import HoverTool, ColorBar, LinearColorMapper, Label
from bokeh.palettes import Spectral5
from bokeh.plotting import curdoc, figure, ColumnDataSource
from bokeh.sampledata.autompg import autompg_clean as df
df = df.copy()
SIZES = list(range(6, 22, 3))
COLORS = Spectral5
# data cleanup
df.cyl = df.cyl.astype(str)
df.yr = df.yr.astype(str)
columns = sorted(df.columns)
discrete = [x for x in columns if df[x].dtype == object]
continuous = [x for x in columns if x not in discrete]
quantileable = [x for x in continuous if len(df[x].unique()) > 20]
def create_figure():
xs = df[x.value].tolist()
ys = df[y.value].tolist()
x_title = x.value.title()
y_title = y.value.title()
name = df['name'].tolist()
kw = dict()
if x.value in discrete:
kw['x_range'] = sorted(set(xs))
if y.value in discrete:
kw['y_range'] = sorted(set(ys))
kw['title'] = "%s vs %s" % (y_title, x_title)
p = figure(plot_height=600, plot_width=800,
tools='pan,box_zoom,wheel_zoom,lasso_select,reset,save',
toolbar_location='above', **kw)
p.xaxis.axis_label = x_title
p.yaxis.axis_label = y_title
if x.value in discrete:
p.xaxis.major_label_orientation = pd.np.pi / 4
if size.value != 'None':
groups = pd.qcut(df[size.value].values, len(SIZES))
sz = [SIZES[xx] for xx in groups.codes]
else:
sz = [9] * len(xs)
if color.value != 'None':
coloring = df[color.value].tolist()
cv_95 = np.percentile(np.asarray(coloring), 95)
mapper = LinearColorMapper(palette=Spectral5,
low=cv_min, high=cv_95)
mapper.low_color = 'blue'
mapper.high_color = 'red'
add_color_bar = True
ninety_degrees = pd.np.pi / 2.
color_bar = ColorBar(color_mapper=mapper, title='',
#title=color.value.title(),
title_text_font_style='bold',
title_text_font_size='20px',
title_text_align='center',
orientation='vertical',
major_label_text_font_size='16px',
major_label_text_font_style='bold',
label_standoff=8,
major_tick_line_color='black',
major_tick_line_width=3,
major_tick_in=12,
location=(0,0))
else:
c = ['#31AADE'] * len(xs)
add_color_bar = False
if add_color_bar:
source = ColumnDataSource(data=dict(x=xs, y=ys,
c=coloring, size=sz, name=name))
else:
source = ColumnDataSource(data=dict(x=xs, y=ys, color=c,
size=sz, name=name))
if add_color_bar:
p.circle('x', 'y', fill_color={'field': 'c',
'transform': mapper},
line_color=None, size='size', source=source)
else:
p.circle('x', 'y', color='color', size='size', source=source)
p.add_tools(HoverTool(tooltips=[('x', '#x'), ('y', '#y'),
('desc', '#name')]))
if add_color_bar:
color_bar_label = Label(text=color.value.title(),
angle=ninety_degrees,
text_color='black',
text_font_style='bold',
text_font_size='20px',
x=25, y=300,
x_units='screen', y_units='screen')
p.add_layout(color_bar, 'right')
p.add_layout(color_bar_label, 'right')
return p
def update(attr, old, new):
layout.children[1] = create_figure()
x = Select(title='X-Axis', value='mpg', options=columns)
x.on_change('value', update)
y = Select(title='Y-Axis', value='hp', options=columns)
y.on_change('value', update)
size = Select(title='Size', value='None',
options=['None'] + quantileable)
size.on_change('value', update)
color = Select(title='Color', value='None',
options=['None'] + quantileable)
color.on_change('value', update)
controls = widgetbox([x, y, color, size], width=200)
layout = row(controls, create_figure())
curdoc().add_root(layout)
curdoc().title = "Crossfilter"
You can add a vertical label to the Colorbar by plotting it on a separate axis and adding a title to this axis. To illustrate this, here's a modified version of Bokeh's standard Colorbar example (found here):
import numpy as np
from bokeh.plotting import figure, output_file, show
from bokeh.models import LogColorMapper, LogTicker, ColorBar
from bokeh.layouts import row
plot_height = 500
plot_width = 500
color_bar_height = plot_height + 11
color_bar_width = 180
output_file('color_bar.html')
def normal2d(X, Y, sigx=1.0, sigy=1.0, mux=0.0, muy=0.0):
z = (X-mux)**2 / sigx**2 + (Y-muy)**2 / sigy**2
return np.exp(-z/2) / (2 * np.pi * sigx * sigy)
X, Y = np.mgrid[-3:3:100j, -2:2:100j]
Z = normal2d(X, Y, 0.1, 0.2, 1.0, 1.0) + 0.1*normal2d(X, Y, 1.0, 1.0)
image = Z * 1e6
color_mapper = LogColorMapper(palette="Viridis256", low=1, high=1e7)
plot = figure(x_range=(0,1), y_range=(0,1), toolbar_location=None,
width=plot_width, height=plot_height)
plot.image(image=[image], color_mapper=color_mapper,
dh=[1.0], dw=[1.0], x=[0], y=[0])
Now, to make the Colorbar, create a separate dummy plot, add the Colorbar to the dummy plot and place it next to the main plot. Add the Colorbar label as the title of the dummy plot and center it appropriately.
color_bar = ColorBar(color_mapper=color_mapper, ticker=LogTicker(),
label_standoff=12, border_line_color=None, location=(0,0))
color_bar_plot = figure(title="My color bar title", title_location="right",
height=color_bar_height, width=color_bar_width,
toolbar_location=None, min_border=0,
outline_line_color=None)
color_bar_plot.add_layout(color_bar, 'right')
color_bar_plot.title.align="center"
color_bar_plot.title.text_font_size = '12pt'
layout = row(plot, color_bar_plot)
show(layout)
This gives the following output image:
One thing to look out for is that color_bar_width is set wide enough to incorporate both the Colorbar, its axes labels and the Colorbar label. If the width is set too small, you will get an error and the plot won't render.
As of Bokeh 0.12.10 there is no built in label available for colorbars. In addition to your approach or something like it, another possibility would be a custom extension, though that is similarly not trivial.
Offhand, a colobar label certainly seems like a reasonable thing to consider. Regarding the notion that it ought to be trivially available, if you polled all users about what they consider should be trivially available, there will be thousands of different suggestions for what to prioritize. As is very often the case in the OSS world, there are far more possible things to do, than there are people to do them (less than 3 in this case). So, would first suggest a GitHub Issue to request the feature, and second, if you have the ability, volunteering to help implement it. Your contribution would be valuable and appreciated by many.
I'm trying to create an scrolling plot window with PyQtGraph. The plot itself has multiple axes. I used this as the basis of the multiple axes. I used this one as the base to do the scrolling bit.
My problem is that for my data, the scrolling plot seems to acquire an y-offset, increasing as time goes on. I also tried using the same data to display in an accumulating plot (though I really would rather to do a scrolling view) and it didn't acquire any y-offset.
This is what it looks at the end of my test sample - missing the effect of y-offset gradually increasing -
Of course, I would like for the y-offset not to appear, the top plot should be identical to the last 50 samples of the bottom plot
Both plots have identical data sets.
The code that I'm using to generate this is:
import pyqtgraph as pg
from pyqtgraph.Qt import QtCore, QtGui
import numpy as np
from time import sleep
win = pg.GraphicsWindow()
win.setWindowTitle('Sliding Window Test')
p1 = win.addPlot()
p1.setLabels(left='Large Range')
## create third ViewBox.
## this time we need to create a new axis as well.
p3 = pg.ViewBox()
ax3 = pg.AxisItem('right')
p1.layout.addItem(ax3, 2, 3)
p1.scene().addItem(p3)
ax3.linkToView(p3)
p3.setXLink(p1)
ax3.setZValue(-10000)
ax3.setLabel('Small Range', color='#ff0000')
win.nextRow()
p5 = win.addPlot()
p5.setLabels(left='Large Range')
## create third ViewBox.
## this time we need to create a new axis as well.
p7 = pg.ViewBox()
ax7 = pg.AxisItem('right')
p5.layout.addItem(ax7, 2, 3)
p5.scene().addItem(p7)
ax7.linkToView(p7)
p7.setXLink(p5)
ax7.setZValue(-10000)
ax7.setLabel('Small Range', color='#ff0000')
## Handle view resizing
def updateViews():
## view has resized; update auxiliary views to match
global p1, p3, p5, p7
p3.setGeometry(p1.vb.sceneBoundingRect())
p7.setGeometry(p5.vb.sceneBoundingRect())
## need to re-update linked axes since this was called
## incorrectly while views had different shapes.
## (probably this should be handled in ViewBox.resizeEvent)
p3.linkedViewChanged(p1.vb, p3.XAxis)
p7.linkedViewChanged(p5.vb, p7.XAxis)
updateViews()
p1.vb.sigResized.connect(updateViews)
p5.vb.sigResized.connect(updateViews)
data1 = []
data3 = []
curve1 = p1.plot()
curve3 = pg.PlotCurveItem(pen='r')
p3.addItem(curve3)
curve5 = p5.plot()
curve7 = pg.PlotCurveItem(pen='r')
p7.addItem(curve7)
data1 = [1000.0*r - 400 for r in np.random.random(size=600)]
data3 = [1.5*r for r in np.random.random(size=600)]
p1.setRange(yRange=(-400, 600))
p3.setRange(yRange=(0, 1.5))
p5.setRange(yRange=(-400, 600))
p7.setRange(yRange=(0, 1.5))
timer = pg.QtCore.QTimer()
r = 0
def update():
global timer
global r
if r > 50:
curve1.setData(data1[r-50:r])
curve3.setData(data3[r-50:r])
curve1.setPos(r - 50, r)
curve3.setPos(r - 50, r)
else:
curve1.setData(data1[:r])
curve3.setData(data3[:r])
curve5.setData(data1[:r])
curve7.setData(data3[:r])
r +=1
if r >= 600:
timer.stop()
timer.timeout.connect(update)
timer.start(100)
## Start Qt event loop unless running in interactive mode or using pyside.
if __name__ == '__main__':
import sys
if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
QtGui.QApplication.instance().exec_()
Simple error: both curves in the top plot are shifted in the y-direction because of these lines:
curve1.setPos(r - 50, r)
curve3.setPos(r - 50, r)
They should instead look like:
curve1.setPos(r - 50, 0)
curve3.setPos(r - 50, 0)
Edit: This was originally on programmers.stackexchange.com, but since I already had some code I thought it might be better here.
I am trying to generate a random math problem/equation. After researching the best (and only) thing I found was this question: Generating random math expression. Because I needed all 4 operations, and the app that I will be using this in is targeted at kids, I wanted to be able to insure that all numbers would be positive, division would come out even, etc, I decided to use a tree.
I have the tree working, and it can generate an equation as well as evaluate it to a number. The problem is that I am having trouble getting it to only use parentheses when needed. I have tried several solutions, that primaraly involve:
Seeing if this node is on the right of the parent node
Seeing if the node is more/less important then it's parent node (* > +, etc).
Seeing if the node & it's parent are of the same type, and if so if the order matters for that operation.
Not that it matters, I am using Swift, and here is what I have so far:
func generateString(parent_node:TreeNode) -> String {
if(self.is_num){
return self.equation!
}
var equation = self.equation!
var left_equation : String = self.left_node!.generateString(self)
var right_equation : String = self.right_node!.generateString(self)
// Conditions for ()s
var needs_parentheses = false
needs_parentheses = parent_node.importance > self.importance
needs_parentheses = (
needs_parentheses
||
(
parent_node.right_node?.isEqualToNode(self)
&&
parent_node.importance <= self.importance
&&
(
parent_node.type != self.type
&&
( parent_node.order_matters != true || self.order_matters != true )
)
)
)
needs_parentheses = (
needs_parentheses
&&
(
!(
self.importance > parent_node.importance
)
)
)
if (needs_parentheses) {
equation = "(\(equation))"
}
return equation.stringByReplacingOccurrencesOfString("a", withString: left_equation).stringByReplacingOccurrencesOfString("b", withString: right_equation)
}
I have not been able to get this to work, and have been banging my head against the wall about it.
The only thing I could find on the subject of removing parentheses is this: How to get rid of unnecessary parentheses in mathematical expression, and I could not figure out how to apply it to my use case. Also, I found this, and I might try to build a parser (using PEGKit), but I wanted to know if anybody had a good idea to either determine where parentheses need to go, or put them everywhere and remove the useless ones.
EDIT: Just to be clear, I don't need someone to write this for me, I am just looking for what it needs to do.
EDIT 2: Since this app will be targeted at kids, I would like to use the least amount of parentheses possible, while still having the equation come out right. Also, the above algorithm does not put enough parentheses.
I have coded a python 3 pgrm that does NOT use a tree, but does successfully generate valid equations with integer solutions and it uses all four operations plus parenthetical expressions. My target audience is 5th graders practicing order of operations (PEMDAS).
872 = 26 * 20 + (3 + 8) * 16 * 2
251 = 256 - 3 - 6 + 8 / 2
367 = 38 * 2 + (20 + 15) + 16 ** 2
260 = 28 * 10 - 18 - 4 / 2
5000 = 40 * 20 / 4 * 5 ** 2
211 = 192 - 10 / 2 / 1 + 24
1519 = 92 * 16 + 6 + 25 + 16
If the python of any interest to you ... I am working on translating the python into JavaScript and make a web page available for students and teachers.