blocks|key|369609|text|由于@Etienne询问如何在不熔化数据的情况下做到这一点(这通常是首选方法，但我认识到在某些情况下这可能是不可能的)，因此我提出了以下替代方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|369610|从原始数据的子集开始：|369611|datos+<-
structure(list(fecha+=+structure(c(1317452400,+1317538800,+1317625200,+
1317711600,+1317798000,+1317884400,+1317970800,+1318057200,+1318143600,+
1318230000,+1318316400,+1318402800,+1318489200,+1318575600,+1318662000,+
1318748400,+1318834800,+1318921200,+1319007600,+1319094000),+class+=+c("POSIXct",+
"POSIXt"),+tzone+=+""),+TempMax+=+c(26.58,+27.78,+27.9,+27.44,+
30.9,+30.44,+27.57,+25.71,+25.98,+26.84,+33.58,+30.7,+31.3,+27.18,+
26.58,+26.18,+25.19,+24.19,+27.65,+23.92),+TempMedia+=+c(22.88,+
22.87,+22.41,+21.63,+22.43,+22.29,+21.89,+20.52,+19.71,+20.73,+
23.51,+23.13,+22.95,+21.95,+21.91,+20.72,+20.45,+19.42,+19.97,+
19.61),+TempMin+=+c(19.34,+19.14,+18.34,+17.49,+16.75,+16.75,+
16.88,+16.82,+14.82,+16.01,+16.88,+17.55,+16.75,+17.22,+19.01,+
16.95,+17.55,+15.21,+14.22,+16.42)),+.Names+=+c("fecha",+"TempMax",+
"TempMedia",+"TempMin"),+row.names+=+c(NA,+20L),+class+=+"data.frame")|code-block|syntax|javascript|369612|您可以通过以下方式获得所需的效果(这也会清除原始绘图代码)：|369613|ggplot(data+=+datos,+aes(x+=+fecha))+%2B
++geom_line(aes(y+=+TempMax,+colour+=+"TempMax"))+%2B
++geom_line(aes(y+=+TempMedia,+colour+=+"TempMedia"))+%2B
++geom_line(aes(y+=+TempMin,+colour+=+"TempMin"))+%2B
++scale_colour_manual("",+
++++++++++++++++++++++breaks+=+c("TempMax",+"TempMedia",+"TempMin"),
++++++++++++++++++++++values+=+c("red",+"green",+"blue"))+%2B
++xlab("+")+%2B
++scale_y_continuous("Temperatura+(C)",+limits+=+c(-10,40))+%2B+
++labs(title="TITULO")|369614|其思想是，通过将colour美学映射到一个常量字符串，为每一行指定一种颜色。选择要在图例中显示的字符串是最简单的。在本例中，它与正在绘制的y变量的名称相同这一事实并不重要；它可以是任何字符串集。这是非常重要的，这是在aes调用中；您正在创建到这个“变量”的映射。|style|CODE|369615|scale_colour_manual现在可以将这些字符串映射到适当的颜色。结果是|369616|📷|atomic|369617|​|369618|在某些情况下，级别和颜色之间的映射需要通过命名手动标度中的值来明确表示(感谢@DaveRGP指出这一点)：|369619|ggplot(data+=+datos,+aes(x+=+fecha))+%2B
++geom_line(aes(y+=+TempMax,+colour+=+"TempMax"))+%2B
++geom_line(aes(y+=+TempMedia,+colour+=+"TempMedia"))+%2B
++geom_line(aes(y+=+TempMin,+colour+=+"TempMin"))+%2B
++scale_colour_manual("",+
++++++++++++++++++++++values+=+c("TempMedia"="green",+"TempMax"="red",+
+++++++++++++++++++++++++++++++++"TempMin"="blue"))+%2B
++xlab("+")+%2B
++scale_y_continuous("Temperatura+(C)",+limits+=+c(-10,40))+%2B+
++labs(title="TITULO")|369620|(给出的数字与之前相同)。对于命名值，可以使用分隔符来设置图例中的顺序，并且可以在值中使用任何顺序。|369621|ggplot(data+=+datos,+aes(x+=+fecha))+%2B
++geom_line(aes(y+=+TempMax,+colour+=+"TempMax"))+%2B
++geom_line(aes(y+=+TempMedia,+colour+=+"TempMedia"))+%2B
++geom_line(aes(y+=+TempMin,+colour+=+"TempMin"))+%2B
++scale_colour_manual("",+
++++++++++++++++++++++breaks+=+c("TempMedia",+"TempMax",+"TempMin"),
++++++++++++++++++++++values+=+c("TempMedia"="green",+"TempMax"="red",+
+++++++++++++++++++++++++++++++++"TempMin"="blue"))+%2B
++xlab("+")+%2B
++scale_y_continuous("Temperatura+(C)",+limits+=+c(-10,40))+%2B+
++labs(title="TITULO")|369622|369623|369624|369625|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/users/742447/etienne-low-d%25c3%25a9carie|1|IMAGE|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/2764e385f3bf7f2f92b40e9976ffa4a4.png|imageAlt|2|https://stackoverflow.com/users/2902740/davergp|3|https://ask.qcloudimg.com/http-save/yehe-900000/0eb205124a0da4d29eeed0fd3ec85fa1.png^0|2|8|0|0|0|0|0|0|8|6|1X|1|30|3|0|0|J|0|0|1|1|0|0|12|8|2|0|0|0|0|0|0|1|3|0|0^^$0|@$1|2|3|4|5|6|7|1S|8|@]|9|@$A|1T|B|1U|1|1V]]|C|$]]|$1|D|3|E|5|6|7|1W|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|1X|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|1Y|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|1Z|8|@]|9|@]|C|$I|J]]|$1|O|3|P|5|6|7|20|8|@$A|21|B|22|Q|R]|$A|23|B|24|Q|R]|$A|25|B|26|Q|R]]|9|@]|C|$]]|$1|S|3|T|5|6|7|27|8|@$A|28|B|29|Q|R]]|9|@]|C|$]]|$1|U|3|V|5|W|7|2A|8|@]|9|@$A|2B|B|2C|1|2D]]|C|$]]|$1|X|3|Y|5|6|7|2E|8|@]|9|@]|C|$]]|$1|Z|3|10|5|6|7|2F|8|@]|9|@$A|2G|B|2H|1|2I]]|C|$]]|$1|11|3|12|5|H|7|2J|8|@]|9|@]|C|$I|J]]|$1|13|3|14|5|6|7|2K|8|@]|9|@]|C|$]]|$1|15|3|16|5|H|7|2L|8|@]|9|@]|C|$I|J]]|$1|17|3|Y|5|6|7|2M|8|@]|9|@]|C|$]]|$1|18|3|V|5|W|7|2N|8|@]|9|@$A|2O|B|2P|1|2Q]]|C|$]]|$1|19|3|Y|5|6|7|2R|8|@]|9|@]|C|$]]|$1|1A|3|-4|5|6|7|2S|8|@]|9|@]|C|$]]]|1B|$1C|$5|1D|1E|1F|C|$1G|1H]]|1I|$5|1J|1E|1K|C|$1L|1M|1N|-4]]|1O|$5|1D|1E|1F|C|$1G|1P]]|1Q|$5|1J|1E|1K|C|$1L|1R|1N|-4]]]]

Since <a href="https://stackoverflow.com/users/742447/etienne-low-d%c3%a9carie">@Etienne</a> asked how to do this without melting the data (which in general is the preferred method, but I recognize there may be some cases where that is not possible), I present the following alternative.

Start with a subset of the original data:

<pre><code>datos &lt;-
structure(list(fecha = structure(c(1317452400, 1317538800, 1317625200, 
1317711600, 1317798000, 1317884400, 1317970800, 1318057200, 1318143600, 
1318230000, 1318316400, 1318402800, 1318489200, 1318575600, 1318662000, 
1318748400, 1318834800, 1318921200, 1319007600, 1319094000), class = c("POSIXct", 
"POSIXt"), tzone = ""), TempMax = c(26.58, 27.78, 27.9, 27.44, 
30.9, 30.44, 27.57, 25.71, 25.98, 26.84, 33.58, 30.7, 31.3, 27.18, 
26.58, 26.18, 25.19, 24.19, 27.65, 23.92), TempMedia = c(22.88, 
22.87, 22.41, 21.63, 22.43, 22.29, 21.89, 20.52, 19.71, 20.73, 
23.51, 23.13, 22.95, 21.95, 21.91, 20.72, 20.45, 19.42, 19.97, 
19.61), TempMin = c(19.34, 19.14, 18.34, 17.49, 16.75, 16.75, 
16.88, 16.82, 14.82, 16.01, 16.88, 17.55, 16.75, 17.22, 19.01, 
16.95, 17.55, 15.21, 14.22, 16.42)), .Names = c("fecha", "TempMax", 
"TempMedia", "TempMin"), row.names = c(NA, 20L), class = "data.frame")
</code></pre>

You can get the desired effect by (and this also cleans up the original plotting code):

<pre><code>ggplot(data = datos, aes(x = fecha)) +
 geom_line(aes(y = TempMax, colour = "TempMax")) +
 geom_line(aes(y = TempMedia, colour = "TempMedia")) +
 geom_line(aes(y = TempMin, colour = "TempMin")) +
 scale_colour_manual("", 
 breaks = c("TempMax", "TempMedia", "TempMin"),
 values = c("red", "green", "blue")) +
 xlab(" ") +
 scale_y_continuous("Temperatura (C)", limits = c(-10,40)) + 
 labs(title="TITULO")
</code></pre>

The idea is that each line is given a color by mapping the <code>colour</code> aesthetic to a constant string. Choosing the string which is what you want to appear in the legend is the easiest. The fact that in this case it is the same as the name of the <code>y</code> variable being plotted is not significant; it could be any set of strings. It is very important that this is inside the <code>aes</code> call; you are creating a mapping to this "variable".

<code>scale_colour_manual</code> can now map these strings to the appropriate colors. The result is
<img src="https://i.stack.imgur.com/XU3cA.png" alt="enter image description here">

In some cases, the mapping between the levels and colors needs to be made explicit by naming the values in the manual scale (thanks to <a href="https://stackoverflow.com/users/2902740/davergp">@DaveRGP</a> for pointing this out):

<pre><code>ggplot(data = datos, aes(x = fecha)) +
 geom_line(aes(y = TempMax, colour = "TempMax")) +
 geom_line(aes(y = TempMedia, colour = "TempMedia")) +
 geom_line(aes(y = TempMin, colour = "TempMin")) +
 scale_colour_manual("", 
 values = c("TempMedia"="green", "TempMax"="red", 
 "TempMin"="blue")) +
 xlab(" ") +
 scale_y_continuous("Temperatura (C)", limits = c(-10,40)) + 
 labs(title="TITULO")
</code></pre>

(giving the same figure as before). With named values, the breaks can be used to set the order in the legend and any order can be used in the values.

<pre><code>ggplot(data = datos, aes(x = fecha)) +
 geom_line(aes(y = TempMax, colour = "TempMax")) +
 geom_line(aes(y = TempMedia, colour = "TempMedia")) +
 geom_line(aes(y = TempMin, colour = "TempMin")) +
 scale_colour_manual("", 
 breaks = c("TempMedia", "TempMax", "TempMin"),
 values = c("TempMedia"="green", "TempMax"="red", 
 "TempMin"="blue")) +
 xlab(" ") +
 scale_y_continuous("Temperatura (C)", limits = c(-10,40)) + 
 labs(title="TITULO")
</code></pre>

<img src="https://i.stack.imgur.com/eRKNt.png" alt="">

blocks|key|369708|text|我真的很喜欢@Brian+Diggs提出的解决方案。然而，在我的例子中，我是在一个循环中创建线条图，而不是显式地给出它们，因为我事先不知道我会有多少个线条图。当我试图修改@Brian的代码时，我遇到了一些正确处理颜色的问题。原来我需要修改美学功能。如果有人有同样的问题，这里是为我工作的代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|369709|我使用了与@Brian相同的数据帧：|369710|data+<-+structure(list(month+=+structure(c(1317452400,+1317538800,+1317625200,+1317711600,+
+++++++++++++++++++++++++++++++++++++++1317798000,+1317884400,+1317970800,+1318057200,+
+++++++++++++++++++++++++++++++++++++++1318143600,+1318230000,+1318316400,+1318402800,+
+++++++++++++++++++++++++++++++++++++++1318489200,+1318575600,+1318662000,+1318748400,+
+++++++++++++++++++++++++++++++++++++++1318834800,+1318921200,+1319007600,+1319094000),+
+++++++++++++++++++++++++++++++++++++class+=+c("POSIXct",+"POSIXt"),+tzone+=+""),
+++++++++++++++++++TempMax+=+c(26.58,+27.78,+27.9,+27.44,+30.9,+30.44,+27.57,+25.71,+
+++++++++++++++++++++++++++++++25.98,+26.84,+33.58,+30.7,+31.3,+27.18,+26.58,+26.18,+
+++++++++++++++++++++++++++++++25.19,+24.19,+27.65,+23.92),+
+++++++++++++++++++TempMed+=+c(22.88,+22.87,+22.41,+21.63,+22.43,+22.29,+21.89,+20.52,
+++++++++++++++++++++++++++++++++19.71,+20.73,+23.51,+23.13,+22.95,+21.95,+21.91,+20.72,+
+++++++++++++++++++++++++++++++++20.45,+19.42,+19.97,+19.61),+
+++++++++++++++++++TempMin+=+c(19.34,+19.14,+18.34,+17.49,+16.75,+16.75,+16.88,+16.82,+
+++++++++++++++++++++++++++++++14.82,+16.01,+16.88,+17.55,+16.75,+17.22,+19.01,+16.95,+
+++++++++++++++++++++++++++++++17.55,+15.21,+14.22,+16.42)),+
++++++++++++++.Names+=+c("month",+"TempMax",+"TempMed",+"TempMin"),+
++++++++++++++row.names+=+c(NA,+20L),+class+=+"data.frame")++|code-block|syntax|javascript|369711|在我的例子中，我动态地生成my.cols和my.names，但我不想让事情变得不必要地复杂，所以我在这里显式地给出了它们。这三行使图例的排序和指定颜色变得更容易。|offset|length|style|CODE|369712|my.cols+<-+heat.colors(3,+alpha=1)
my.names+<-+c("TempMin",+"TempMed",+"TempMax")
names(my.cols)+<-+my.names|369713|下面是剧情：|369714|p+<-++ggplot(data,+aes(x+=+month))

for+(i+in+1:3){
++p+<-+p+%2B+geom_line(aes_(y+=+as.name(names(data[i%2B1])),+colour+=+
colnames(data[i%2B1])))#as.character(my.names[i])))
}
p+%2B+scale_colour_manual("",+
++++++++++++++++++++++++breaks+=+as.character(my.names),
++++++++++++++++++++++++values+=+my.cols)
p|369715|​|369716|📷|atomic|369717|369718|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/92ecc25687881f257dff90d90e62889a.png|imageAlt^0|0|0|0|D|7|L|8|0|0|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|19|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1A|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|1B|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|1C|8|@$K|1D|L|1E|M|N]|$K|1F|L|1G|M|N]]|9|@]|A|$]]|$1|O|3|P|5|F|7|1H|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|1I|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|1J|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|1K|8|@]|9|@]|A|$]]|$1|W|3|X|5|Y|7|1L|8|@]|9|@$K|1M|L|1N|1|1O]]|A|$]]|$1|Z|3|V|5|6|7|1P|8|@]|9|@]|A|$]]|$1|10|3|-4|5|6|7|1Q|8|@]|9|@]|A|$]]]|11|$12|$5|13|14|15|A|$16|17|18|-4]]]]

I really like the solution proposed by @Brian Diggs. However, in my case, I create the line plots in a loop rather than giving them explicitly because I do not know apriori how many plots I will have. When I tried to adapt the @Brian's code I faced some problems with handling the colors correctly. Turned out I needed to modify the aesthetic functions. In case someone has the same problem, here is the code that worked for me. 

I used the same data frame as @Brian:

<pre><code>data &lt;- structure(list(month = structure(c(1317452400, 1317538800, 1317625200, 1317711600, 
 1317798000, 1317884400, 1317970800, 1318057200, 
 1318143600, 1318230000, 1318316400, 1318402800, 
 1318489200, 1318575600, 1318662000, 1318748400, 
 1318834800, 1318921200, 1319007600, 1319094000), 
 class = c("POSIXct", "POSIXt"), tzone = ""),
 TempMax = c(26.58, 27.78, 27.9, 27.44, 30.9, 30.44, 27.57, 25.71, 
 25.98, 26.84, 33.58, 30.7, 31.3, 27.18, 26.58, 26.18, 
 25.19, 24.19, 27.65, 23.92), 
 TempMed = c(22.88, 22.87, 22.41, 21.63, 22.43, 22.29, 21.89, 20.52,
 19.71, 20.73, 23.51, 23.13, 22.95, 21.95, 21.91, 20.72, 
 20.45, 19.42, 19.97, 19.61), 
 TempMin = c(19.34, 19.14, 18.34, 17.49, 16.75, 16.75, 16.88, 16.82, 
 14.82, 16.01, 16.88, 17.55, 16.75, 17.22, 19.01, 16.95, 
 17.55, 15.21, 14.22, 16.42)), 
 .Names = c("month", "TempMax", "TempMed", "TempMin"), 
 row.names = c(NA, 20L), class = "data.frame") 
</code></pre>

In my case, I generate <code>my.cols</code> and <code>my.names</code> dynamically, but I don't want to make things unnecessarily complicated so I give them explicitly here. These three lines make the ordering of the legend and assigning colors easier.

<pre><code>my.cols &lt;- heat.colors(3, alpha=1)
my.names &lt;- c("TempMin", "TempMed", "TempMax")
names(my.cols) &lt;- my.names
</code></pre>

And here is the plot:

<pre><code>p &lt;- ggplot(data, aes(x = month))

for (i in 1:3){
 p &lt;- p + geom_line(aes_(y = as.name(names(data[i+1])), colour = 
colnames(data[i+1])))#as.character(my.names[i])))
}
p + scale_colour_manual("", 
 breaks = as.character(my.names),
 values = my.cols)
p
</code></pre>

<a href="https://i.stack.imgur.com/z47MA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/z47MA.png" alt="enter image description here"></a>

I have a question about legends in ggplot2. I managed to plot three lines in the same graph and want to add a legend with the three colors used. This is the code used

<pre><code>library(ggplot2) 
require(RCurl)

link&lt;-getURL("https://dl.dropbox.com/s/ds5zp9jonznpuwb/dat.txt")
datos&lt;- read.csv(textConnection(link),header=TRUE,sep=";")
datos$fecha &lt;- as.POSIXct(datos[,1], format="%d/%m/%Y") 

temp = ggplot(data=datos,aes(x=fecha, y=TempMax,colour="1")) + 
 geom_line(colour="red") + opts(title="TITULO") +
 ylab("Temperatura (C)") + xlab(" ") + 
 scale_y_continuous(limits = c(-10,40)) + 
 geom_line(aes(x=fecha, y=TempMedia,colour="2"),colour="green") + 
 geom_line(aes(x=fecha, y=TempMin,colour="2"),colour="blue") +
 scale_colour_manual(values=c("red","green","blue"))

temp
</code></pre>

and the output

<img src="https://i.stack.imgur.com/4LqYa.png" alt="ggplot three lines">

I'd like to add a legend with the three colours used and the name of the variable (TempMax,TempMedia and TempMin). I have tried 

<pre><code>scale_colour_manual
</code></pre>

but can't find the exact way.

Unfortunately original data were deleted from linked site and could not be recovered. But they came from meteo data files with this format

<pre><code>"date","Tmax","Tmin","Tmed","Precip.diaria","Wmax","Wmed"
2000-07-31 00:00:00,-1.7,-1.7,-1.7,-99.9,20.4,20.4
2000-08-01 00:00:00,22.9,19,21.11,-99.9,6.3,2.83
2000-08-03 00:00:00,24.8,12.3,19.23,-99.9,6.8,3.87
2000-08-04 00:00:00,20.3,9.4,14.4,-99.9,8.3,5.29
2000-08-08 00:00:00,25.7,14.4,19.5,-99.9,7.9,3.22
2000-08-09 00:00:00,29.8,16.2,22.14,-99.9,8.5,3.27
2000-08-10 00:00:00,30,17.8,23.5,-99.9,7.7,3.61
2000-08-11 00:00:00,27.5,17,22.68,-99.9,8.8,3.85
2000-08-12 00:00:00,24,13.3,17.32,-99.9,8.4,3.49
</code></pre>

Add legend to ggplot2 line plot

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有一个关于ggplot2传奇的问题。我设法在同一张图中绘制了三条线，并希望使用这三种颜色添加一个图例。这是使用的代码library(ggplot2) require(RCurl)link<-getURL("https://dl.dropbox.com/s/ds5zp9jonznpuwb/dat.txt")dat...

问将图例添加到ggplot2线形图
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