How to change tick mark labels in ggplot2? - r

This is a relatively straightforward question, however, I was unable to find an answer. Likewise, I am not used to posting at Stackoverflow so I apologise for any kind of errors.
I currently have a Multiplot Facet that displays the variation in animal activity (Y) and day length on a seasonal level (in this case, two seasons).
As you see on the X axis, there are numbers such as 0.45, 0.47, etc. These represent time in numeric form. The issue is, is that I would like to convert 0.45 and etc to hours (it should be noted that they are not represented as dates). That is, 0.45 should represent 10, 0.47 should represent 10.2 etc. While I attempted to manually do this in excel...the scatter plots are well..not very scattered when plotting them. That is, I simply converted 10:02:00 to 10.2 (therefore, they do not represent actual dates in R)
Is there a way to either
1. manually change the numeric daylength (i.e. 0.45) to the hours that they represent?
2. Shorten the tick marks for the actual hours for both facets so that they do not seemed as scattered?
Likewise, is all of this possible while keeping both facets in place?
Here is the script that I use for the plot:
ii$season = factor(ii$season, levels = c("Winter","Summer"))
ii <- ii%>%
mutate(season = ifelse(month2 %in% c( 6,7, 8), "Winter",
ifelse(month2 %in% c(12,1,2), "Summer","Error")))
Plot <- ggplot(ii, aes(daylength, newavx2)) +
geom_point() + geom_smooth()+
ggtitle("Activity and Daylength by Season") +
xlab("Daylength") + ylab("Activity") +
theme(plot.title = element_text(lineheight=.8, face="bold",size = 20)) +
theme(text = element_text(size=18))
Plot + facet_grid(.~season, scales = "free_x") +
theme(strip.background = element_blank())
It should be noted that for the second plot, the variable daylength is simply replaced by 'hours' Thank you so much for your help

Related

R, ggplot, How do I keep related points together when using jitter?

One of the variables in my data frame is a factor denoting whether an amount was gained or spent. Every event has a "gain" value; there may or may not be a corresponding "spend" amount. Here is an image with the observations overplotted:
Adding some random jitter helps visually, however, the "spend" amounts are divorced from their corresponding gain events:
I'd like to see the blue circles "bullseyed" in their gain circles (where the "id" are equal), and jittered as a pair. Here are some sample data (three days) and code:
library(ggplot2)
ccode<-c(Gain="darkseagreen",Spend="darkblue")
ef<-data.frame(
date=as.Date(c("2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03")),
site=c("Castle","Temple","Temple","Temple","Temple","Temple","Palace","Palace","Castle","Castle","Castle","Temple","Temple","Palace","Palace","Castle","Castle","Castle","Castle","Castle","Temple","Temple","Palace","Castle","Temple","Temple","Temple","Temple","Temple","Palace","Palace","Castle","Castle","Castle","Temple","Temple","Palace","Palace","Castle","Castle","Castle","Castle","Castle","Temple","Temple","Palace"),
id=c("C123","T101","T93","T94","T95","T96","P102","P96","C126","C127","C128","T100","T98","P100","P98","C129","C130","C131","C132","C133","T104","T99","P99","C123","T101","T93","T94","T95","T96","P102","P96","C126","C127","C128","T100","T98","P100","P98","C129","C130","C131","C132","C133","T104","T99","P99"),
gainspend=c("Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend"),
amount=c(6,14,34,31,3,10,6,14,2,16,16,14,1,1,15,11,8,7,2,10,15,4,3,NA,NA,4,5,NA,NA,NA,NA,NA,NA,2,NA,1,NA,3,NA,NA,2,NA,NA,2,NA,3))
#▼ 3 day, points centered
ggplot(ef,aes(date,site)) +
geom_point(aes(size=amount,color=gainspend),alpha=0.5) +
scale_color_manual(values=ccode) +
scale_size_continuous(range=c(1,15),breaks=c(5,10,20))
#▼ 3 day, jitted
ggplot(ef,aes(date,site)) +
geom_point(aes(size=amount,color=gainspend),alpha=0.5,position=position_jitter(w=0,h=0.2)) +
scale_color_manual(values=ccode) +
scale_size_continuous(range=c(1,15),breaks=c(5,10,20))
My main idea is the old "add jitter manually" approach. I'm wondering if a nicer approach could be something like plotting little pie charts as points a la package scatterpie.
In this case you could add a random number for the amount of jitter to each ID so points within groups will be moved the same amount. This takes doing work outside of ggplot2.
First, draw the "jitter" to add for each ID. Since a categorical axis is 1 unit wide, I choose numbers between -.3 and .3. I use dplyr for this work and set the seed so you will get the same results.
library(dplyr)
set.seed(16)
ef2 = ef %>%
group_by(id) %>%
mutate(jitter = runif(1, min = -.3, max = .3)) %>%
ungroup()
Then the plot. I use a geom_blank() layer so that the categorical site axis is drawn before I add the jitter. I convert site to be numeric from a factor and add the jitter on; this only works for factors so luckily categorical axes in ggplot2 are based on factors.
Now paired ID's move together.
ggplot(ef2, aes(x = date, y = site)) +
geom_blank() +
geom_point(aes(size = amount, color = gainspend,
y = as.numeric(factor(site)) + jitter),
alpha=0.5) +
scale_color_manual(values = ccode) +
scale_size_continuous(range = c(1, 15), breaks = c(5, 10, 20))
#> Warning: Removed 15 rows containing missing values (geom_point).
Created on 2021-09-23 by the reprex package (v2.0.0)
You can add some jitter by id outside the ggplot() call.
jj <- data.frame(id = unique(ef$id), jtr = runif(nrow(ef), -0.3, 0.3))
ef <- merge(ef, jj, by = 'id')
ef$sitej <- as.numeric(factor(ef$site)) + ef$jtr
But you need to make site integer/numeric to do this. So when it comes to making the plot, you need to manually add axis labels with scale_y_continuous(). (Update: the geom_blank() trick from aosmith above is a better solution!)
ggplot(ef,aes(date,sitej)) +
geom_point(aes(size=amount,color=gainspend),alpha=0.5) +
scale_color_manual(values=ccode) +
scale_size_continuous(range=c(1,15),breaks=c(5,10,20)) +
scale_y_continuous(breaks = 1:3, labels= sort(unique(ef$site)))
This seems to work, but there are still a few gain/spend circles without a partner--perhaps there is a problem with the id variable.
Perhaps someone else has a better approach!

X axis dates not in chronological order

I'm a massive Rstudio novice so I have scoured the related questions etc. but I am still having trouble with organising my graph properly. I am having trouble getting my graph to show dates in the correct, chronological order. Wondering if I could get someone to have a look at my code and data and see what i'm doing wrong (explained very simply please, I am a novice).
I am currently reading in a CSV file, which is set up like this 1:
AdD = date sample taken, AdT = time sample taken, AdV = Concentration value - these are water samples and only consist of these two samples across the two months (one per month)
and I get the graph:
The graph shows the 5th month first on the x axis, when I want it in chronological order (aka April - 4th month) to appear first.
My code is as follows (please disregard the geom_hline and axis elements blank - this is one of 6 graphs in a facet and those aren't relevant to the date problem I think/hope) :
F1ambH <- read_csv("data 1 Amb.csv")
f1ambH <- ggplot(data=F1ambH, aes(x=AhD, y=AhV))+ geom_point() +theme_bw()+labs(y= "Concentration (µg/L)", x = "Sample Date")
f1ambH <- f1ambH + geom_hline(yintercept=1.1, linetype="dashed", color="steelblue")+ theme(axis.title.x = element_blank())+ theme(axis.title.y = element_text(face = "bold", size = 11))
f1ambH
I have also tried mutating the data like this:
F1ambH <- read_csv("data 1 Amb.csv") %>% mutate(dates = dmy(AhD))
f1ambH <- ggplot(data=dates, aes(x=AhD, y=AhV))+ geom_point() +theme_bw()+labs(y= "Concentration (µg/L)", x = "Sample Date")
which produces this graph:
Which shows the dates correctly, but the two points on the graph don't have a corresponding x axis tick which I need (of which I feel like ive exhausted my options in trying to fix
so if I can fix either problem then that would be amazing.
EDT:
Using the +scale_x_date(breaks=unique(F1ambH$dates)) as suggested by the first comment seems to solve my problem, but the points are now at the opposite side of the graph and look horrendous, is there a way to clean it up?
Figure
Use your second solution, but use
+scale_x_date(breaks=unique(dates))
to specify where you want the breakpoints.
If you make x variable as factor and add it before plot, it keeps the order:
F1ambH$AhD <- factor(F1ambH$AhD,levels=unique(F1ambH$AhD),order=TRUE)
f1ambH <- ggplot(data=F1ambH, aes(x=AhD, y=AhV))+ geom_point() +theme_bw()+labs(y=
"Concentration (µg/L)", x = "Sample Date")
f1ambH <- f1ambH + geom_hline(yintercept=1.1, linetype="dashed", color="steelblue")+
theme(axis.title.x = element_blank())+ theme(axis.title.y = element_text(face =
"bold", size = 11))
f1ambH
Even you can have any order you prefer:
F1ambH$AhD <- factor(F1ambH$AhD,levels=c(your preference order),order=TRUE)

How to add secondary axis while making barplot using ggplot2

I have a dataset of a type as shown
Seasons A B C A1 B1 C1
Winter 97 94 87 0.2 0.4 0.3
Summer 92 94 101 1 0.7 0.3
There are values for each season (Summer, Winter, autumn, spring) and with variables from (A to E) and (A1 to E1). While drawing a barplot using ggplot2, the bar height of A1 to E1 is very less due to their low values and I wish to move them to the secondary axis but I don't know how to do that. Please suggest the code. I am sharing my code until now.
library(readxl)
library(ggplot2)
library(readxl)
cell_viability_data <- read_excel("C:/Users/CEZ178522/Downloads/ananya/Cell_viability.xlsx")
cell_viability_data
plot1 <- ggplot(data=cell_viability_data, aes(x=Seasons, y= CellViability, fill= Types)) +
geom_bar(stat="identity", position=position_dodge()) +
labs(title = "Seasonal Cell Viability") +
theme(axis.text.x = element_text(colour = "grey1", size = 10),
axis.text.y = element_text(colour = "grey1", size = 10),
plot.title = element_text(hjust = 0.5))
plot1
I need the small bars to move to secondary axis
Secondary y-axes were for a long time banned in ggplot because they usually do more damage than good. The only option for now is to display an auxiliary, secondary y-axis which has a direct, proportional transformation from the primary y-axis. In other words, the secondary y-axis is a supplemental axis which displays the same information, but on a different scale (thing Celcius and Fahrenheit).
What you are asking is to have a subset of data points inflated by some arbitrary value, so they are "on par" with the remaining. Consider this: Can you, by choice of scaling constant, make values A1-E1 appear much higher than values A-E? Can you, by choice of scaling constant, make values A1-E1 appear much, much lower than values A-E? Can you, by choice of scaling constant, make values A1-E1 be "on par" with A-E, but always slighter lower? If so, to any question, your data visualisation cannot be trusted.
Consider instead: What is the important comparison you are trying to make? Season-to-season for each type? A vs. A1? Take out a pen and paper, and try to sketch what you want to compare, and what issues you are encountering when making a comparison. Then you are ready to make the visualisation in R/ggplot.

How to create geom_boxplot with large amount of continuous x-variables

I have a data frame which contains x-axis numeric bins and continuous y-axis data across multiple categories. Initially, I created a boxplot by making the x-axis bins "factors", and doing a boxplot of the melted data. Reproducible data:
x <- seq(1,10,by=1)
y1 <- rnorm(10, mean=3)
y2 <- rnorm(10, mean=10)
y3<- rnorm(10, mean=1)
y4<- rnorm(10, mean=8)
y5<- rnorm(10, mean=12)
df <- data.frame(x,y1,y2,y3,y4,y5)
df.m <- melt(df, id="x")
My code to create the x-axis data as a factor:
df.m$x <- as.factor(df.m$x)
My ggplot:
ggplot(df.m, aes(x=x, y=value))+
geom_boxplot(notch=FALSE, outlier.shape=NA, fill="red", alpha=0.1)+
theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1))
The resulting plot:
:
The problem is that I cannot use x-axis numeric spacing because the x-axis is categorized as a factor, which has equal spacing. I want to be able to use something like scale_x_continuous to manipulate the axis breaks and spacing to, say, an interval of 2, rather than a boxplot every 1, but when I try to plot the data with the x-axis "as.numeric", I just get one boxplot of all of the data:
Any suggestions for a way to get this continuous-looking boxplot curve (the first image) while still being able to control the numeric properties of the x-axis? Thanks!
Here is a way using the original data you posted on Google - which actually was much more helpful, IMO.
ggplot(df, aes(x=CH, y=value,group=CH))+
geom_boxplot(notch=FALSE, outlier.shape=NA, fill="red", alpha=0.2)+
scale_x_log10()
So, as #BenBolker said before he deleted his answer(??), you should leave the x-variable (CH) as numeric, and set group=CH in the call to aes(...).
With your real data there is another problem though. Your CH is more or less logarithmically spaced, so there are about as many points < 1 as there are between 1 - 10, etc. ggplot wants to make the boxes all the same size, so with a linear x-axis the box width is smaller than the line width, and you don't see the boxes at all. Changing the x-axis to a logarithmic scale fixes that, more or less.
Don't make x a factor. You need to aesthetically map a group that is a factor determining which box the value is associated with, luckily, after melting, this is what you variable column is:
ggplot(df.m, aes(x = x, y = value, group = variable)) +
geom_boxplot()
As x is still numeric, you can give it whatever values you want within a specific variable level and the boxplot will show up at that spot. Or you could transform the x axis, etc.

Understanding dates and plotting a histogram with ggplot2 in R

Main Question
I'm having issues with understanding why the handling of dates, labels and breaks is not working as I would have expected in R when trying to make a histogram with ggplot2.
I'm looking for:
A histogram of the frequency of my dates
Tick marks centered under the matching bars
Date labels in %Y-b format
Appropriate limits; minimized empty space between edge of grid space and outermost bars
I've uploaded my data to pastebin to make this reproducible. I've created several columns as I wasn't sure the best way to do this:
> dates <- read.csv("http://pastebin.com/raw.php?i=sDzXKFxJ", sep=",", header=T)
> head(dates)
YM Date Year Month
1 2008-Apr 2008-04-01 2008 4
2 2009-Apr 2009-04-01 2009 4
3 2009-Apr 2009-04-01 2009 4
4 2009-Apr 2009-04-01 2009 4
5 2009-Apr 2009-04-01 2009 4
6 2009-Apr 2009-04-01 2009 4
Here's what I tried:
library(ggplot2)
library(scales)
dates$converted <- as.Date(dates$Date, format="%Y-%m-%d")
ggplot(dates, aes(x=converted)) + geom_histogram()
+ opts(axis.text.x = theme_text(angle=90))
Which yields this graph. I wanted %Y-%b formatting, though, so I hunted around and tried the following, based on this SO:
ggplot(dates, aes(x=converted)) + geom_histogram()
+ scale_x_date(labels=date_format("%Y-%b"),
+ breaks = "1 month")
+ opts(axis.text.x = theme_text(angle=90))
stat_bin: binwidth defaulted to range/30. Use 'binwidth = x' to adjust this.
That gives me this graph
Correct x axis label format
The frequency distribution has changed shape (binwidth issue?)
Tick marks don't appear centered under bars
The xlims have changed as well
I worked through the example in the ggplot2 documentation at the scale_x_date section and geom_line() appears to break, label, and center ticks correctly when I use it with my same x-axis data. I don't understand why the histogram is different.
Updates based on answers from edgester and gauden
I initially thought gauden's answer helped me solve my problem, but am now puzzled after looking more closely. Note the differences between the two answers' resulting graphs after the code.
Assume for both:
library(ggplot2)
library(scales)
dates <- read.csv("http://pastebin.com/raw.php?i=sDzXKFxJ", sep=",", header=T)
Based on #edgester's answer below, I was able to do the following:
freqs <- aggregate(dates$Date, by=list(dates$Date), FUN=length)
freqs$names <- as.Date(freqs$Group.1, format="%Y-%m-%d")
ggplot(freqs, aes(x=names, y=x)) + geom_bar(stat="identity") +
scale_x_date(breaks="1 month", labels=date_format("%Y-%b"),
limits=c(as.Date("2008-04-30"),as.Date("2012-04-01"))) +
ylab("Frequency") + xlab("Year and Month") +
theme_bw() + opts(axis.text.x = theme_text(angle=90))
Here is my attempt based on gauden's answer:
dates$Date <- as.Date(dates$Date)
ggplot(dates, aes(x=Date)) + geom_histogram(binwidth=30, colour="white") +
scale_x_date(labels = date_format("%Y-%b"),
breaks = seq(min(dates$Date)-5, max(dates$Date)+5, 30),
limits = c(as.Date("2008-05-01"), as.Date("2012-04-01"))) +
ylab("Frequency") + xlab("Year and Month") +
theme_bw() + opts(axis.text.x = theme_text(angle=90))
Plot based on edgester's approach:
Plot based on gauden's approach:
Note the following:
gaps in gauden's plot for 2009-Dec and 2010-Mar; table(dates$Date) reveals that there are 19 instances of 2009-12-01 and 26 instances of 2010-03-01 in the data
edgester's plot starts at 2008-Apr and ends at 2012-May. This is correct based on a minimum value in the data of 2008-04-01 and a max date of 2012-05-01. For some reason gauden's plot starts in 2008-Mar and still somehow manages to end at 2012-May. After counting bins and reading along the month labels, for the life of me I can't figure out which plot has an extra or is missing a bin of the histogram!
Any thoughts on the differences here? edgester's method of creating a separate count
Related References
As an aside, here are other locations that have information about dates and ggplot2 for passers-by looking for help:
Started here at learnr.wordpress, a popular R blog. It stated that I needed to get my data into POSIXct format, which I now think is false and wasted my time.
Another learnr post recreates a time series in ggplot2, but wasn't really applicable to my situation.
r-bloggers has a post on this, but it appears outdated. The simple format= option did not work for me.
This SO question is playing with breaks and labels. I tried treating my Date vector as continuous and don't think it worked so well. It looked like it was overlaying the same label text over and over so the letters looked kind of odd. The distribution is sort of correct but there are odd breaks. My attempt based on the accepted answer was like so (result here).
UPDATE
Version 2: Using Date class
I update the example to demonstrate aligning the labels and setting limits on the plot. I also demonstrate that as.Date does indeed work when used consistently (actually it is probably a better fit for your data than my earlier example).
The Target Plot v2
The Code v2
And here is (somewhat excessively) commented code:
library("ggplot2")
library("scales")
dates <- read.csv("http://pastebin.com/raw.php?i=sDzXKFxJ", sep=",", header=T)
dates$Date <- as.Date(dates$Date)
# convert the Date to its numeric equivalent
# Note that Dates are stored as number of days internally,
# hence it is easy to convert back and forth mentally
dates$num <- as.numeric(dates$Date)
bin <- 60 # used for aggregating the data and aligning the labels
p <- ggplot(dates, aes(num, ..count..))
p <- p + geom_histogram(binwidth = bin, colour="white")
# The numeric data is treated as a date,
# breaks are set to an interval equal to the binwidth,
# and a set of labels is generated and adjusted in order to align with bars
p <- p + scale_x_date(breaks = seq(min(dates$num)-20, # change -20 term to taste
max(dates$num),
bin),
labels = date_format("%Y-%b"),
limits = c(as.Date("2009-01-01"),
as.Date("2011-12-01")))
# from here, format at ease
p <- p + theme_bw() + xlab(NULL) + opts(axis.text.x = theme_text(angle=45,
hjust = 1,
vjust = 1))
p
Version 1: Using POSIXct
I try a solution that does everything in ggplot2, drawing without the aggregation, and setting the limits on the x-axis between the beginning of 2009 and the end of 2011.
The Target Plot v1
The Code v1
library("ggplot2")
library("scales")
dates <- read.csv("http://pastebin.com/raw.php?i=sDzXKFxJ", sep=",", header=T)
dates$Date <- as.POSIXct(dates$Date)
p <- ggplot(dates, aes(Date, ..count..)) +
geom_histogram() +
theme_bw() + xlab(NULL) +
scale_x_datetime(breaks = date_breaks("3 months"),
labels = date_format("%Y-%b"),
limits = c(as.POSIXct("2009-01-01"),
as.POSIXct("2011-12-01")) )
p
Of course, it could do with playing with the label options on the axis, but this is to round off the plotting with a clean short routine in the plotting package.
I know this is an old question, but for anybody coming to this in 2021 (or later), this can be done much easier using the breaks= argument for geom_histogram() and creating a little shortcut function to make the required sequence.
dates <- read.csv("http://pastebin.com/raw.php?i=sDzXKFxJ", sep=",", header=T)
dates$Date <- lubridate::ymd(dates$Date)
by_month <- function(x,n=1){
seq(min(x,na.rm=T),max(x,na.rm=T),by=paste0(n," months"))
}
ggplot(dates,aes(Date)) +
geom_histogram(breaks = by_month(dates$Date)) +
scale_x_date(labels = scales::date_format("%Y-%b"),
breaks = by_month(dates$Date,2)) +
theme(axis.text.x = element_text(angle=90))
I think the key thing is that you need to do the frequency calculation outside of ggplot. Use aggregate() with geom_bar(stat="identity") to get a histogram without the reordered factors. Here is some example code:
require(ggplot2)
# scales goes with ggplot and adds the needed scale* functions
require(scales)
# need the month() function for the extra plot
require(lubridate)
# original data
#df<-read.csv("http://pastebin.com/download.php?i=sDzXKFxJ", header=TRUE)
# simulated data
years=sample(seq(2008,2012),681,replace=TRUE,prob=c(0.0176211453744493,0.302496328928047,0.323054331864905,0.237885462555066,0.118942731277533))
months=sample(seq(1,12),681,replace=TRUE)
my.dates=as.Date(paste(years,months,01,sep="-"))
df=data.frame(YM=strftime(my.dates, format="%Y-%b"),Date=my.dates,Year=years,Month=months)
# end simulated data creation
# sort the list just to make it pretty. It makes no difference in the final results
df=df[do.call(order, df[c("Date")]), ]
# add a dummy column for clarity in processing
df$Count=1
# compute the frequencies ourselves
freqs=aggregate(Count ~ Year + Month, data=df, FUN=length)
# rebuild the Date column so that ggplot works
freqs$Date=as.Date(paste(freqs$Year,freqs$Month,"01",sep="-"))
# I set the breaks for 2 months to reduce clutter
g<-ggplot(data=freqs,aes(x=Date,y=Count))+ geom_bar(stat="identity") + scale_x_date(labels=date_format("%Y-%b"),breaks="2 months") + theme_bw() + opts(axis.text.x = theme_text(angle=90))
print(g)
# don't overwrite the previous graph
dev.new()
# just for grins, here is a faceted view by year
# Add the Month.name factor to have things work. month() keeps the factor levels in order
freqs$Month.name=month(freqs$Date,label=TRUE, abbr=TRUE)
g2<-ggplot(data=freqs,aes(x=Month.name,y=Count))+ geom_bar(stat="identity") + facet_grid(Year~.) + theme_bw()
print(g2)
The error graph this under the title "Plot based on Gauden's approach" is due to the binwidth parameter:
... + Geom_histogram (binwidth = 30, color = "white") + ...
If we change the value of 30 to a value less than 20, such as 10, you will get all frequencies.
In statistics the values are more important than the presentation is more important a bland graphic to a very pretty picture but with errors.

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