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ggplot图例标签内的希腊字母,符号和换行符

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我在尝试着

  • 有换行符(自动或强制)

  • 证明文本的合理性(左侧或左侧和右侧)

  • 有希腊字母和百分号

在gglot图例标签内 .

我已经尝试了几种方法,但我似乎无法将我读到的所有技巧结合起来 .

我可以通过在标签中插入 \n 来获取换行符,但这似乎不适用于希腊字母,而不适用于图例标签 . 或者我可以通过组合 mtext()bquote() 在基础图中使用换行符和希腊字母将一段文本插入到图中,( EDIT )但正如Gregor在评论部分中所指出的,这不适用于 ggplot . 下面我将 listpaste0() 组合在一起,将文字传递给图例标签:问题是我找不到插入希腊字母的方法,例如:伽马 .

感谢你的建议 .

这是一个MWE我的一次尝试( Edit: 改进了MWE):

label1.line1 <- "Not much to say about this one"
label2.line1 <- "blabla blabla, blabla blabla, blee blee blee (bling, bling, bling),"
label2.line2 <- paste0("(", "1900-2014: g = 1.50%, gamma = 2.75%, and r = 2.30%",")")
label3.line1 <- "blabla blabla, blabla blabla, blee blee blee (bling, bling, bling),"
label3.line2 <- paste0("(", "1900-2014: g = 2.50%, gamma = 1.75%, and r = 2.30%",")")
labels_fixed <- list(
    label1.line1, 
    paste0(label2.line1, "\n", label2.line2),
    paste0(label3.line1, "\n", label3.line2)
)
library(ggplot2)
library(scales)
library(grid)  # provides unit() function used to tweak spacing inside legend

ggplot(data = mtcars, aes(x = mpg, y = wt, group = factor(cyl), colour = factor(cyl), shape = factor(cyl))) + 
geom_line() + geom_point(size = 3) + theme_bw() + 
scale_shape_manual(name = "Details", values = c(17, 21, 15), 
    labels = labels_fixed) + 
scale_colour_manual(name = "Details", values = c("darkred", "darkgreen", "darkblue"), 
    labels = labels_fixed) + 
theme(legend.key = element_blank(), 
      legend.position = c(.65, .8), 
      legend.background = element_rect(colour = "black"), 
      legend.key.size = unit(2, "lines"), 
      legend.text = element_text(size = 15))

一个小问题是图例文本要小得多,因此需要调整图例行间距:我能够调整 legend.key.sizelegend.text 以获得比默认值更好的结果,这太过于局促 .

我还尝试了另一个涉及 cat(strwrap("long label here"), sep = "\n") 的建议,但我无法解决这个问题 . 我也尝试了 atop 但是这使得每条线太小而且实现所需堆叠所需的嵌套是乏味的 .

有没有办法得到希腊字母?

enter image description here

以下是一些我无法工作的有用建议,例如:在1和2中提到了 mtext()bquote() 的组合:

1 回答

  • 27

    巴蒂斯特的建议很明显:unicode走了很长一段路 . 用 \u03B3 替换上面的每个gamma实例,它将显示为希腊语 . 惊人!

    可以使用 cairo 设备(ref)进行打印:

    library(Cairo)
    cairo_pdf(file = "ggplot-greek.pdf", width = 8, height = 5)
    ## ggplot object created here
    dev.off()
    

    也有效: ggsave("greek.pdf", device = cairo_pdf)

    以下是我发现有用的unicode符号选择:

    "\U016B" = ū
    "\U016A" = Ū
    "\U00FB" = û
    "\U00DB" = Û
    "\U0233" = ȳ
    "\U0232" = Ȳ
    "\U0177" = ŷ
    "\U0176" = Ŷ
    "\U0113" = ē
    "\U0112" = Ē
    "\u00EA" = ê
    "\U00CA" = Ê
    "\U003BC\U2080" = μ₀
    "\U003BC\U2081" = μ₁
    "R\U00B2" = R²
    "\u221E" = ∞
    "\u2248" = ≈
    "\U2260" = ≠ 
    "\u03C3/\u221An" = σ/√n
    

    可悲的是,并非所有特殊字符都具有相同的unicode . 例如,有一个用于y-hat的unicode,但没有用于x-hat的unicode . 可以将字母x与unicode栏组合在一起,如 "x\u0305" = x̅"p\u0302" = p̂ ,但这似乎打印得不是很好 .

    我也很难打印希腊unicode作为轴标签,因此在这些情况下,我使用 annotate() 选项 coord_cartesian(clip = "off") 以确保打印在轴下方的标签不会被剪裁("on"是默认剪裁行为) .

    有时您可以直接使用该字符,例如:

    myplot + labs(title  = "±")
    

    当unicode失败时,您可以尝试 expression() ,例如

    title = expression(paste("z = (", bar(x), "-\u03BC)/(\u03C3/\u221An)", sep = ""))  
    library(ggplot2)
    ggplot() + labs(title = title) + theme_bw()
    

    title

    为方便起见,我在下面复制了一些常用的希腊字母'unicodes . 可以找到更多的unicodes,例如http://en.wikipedia.org/wiki/List_of_Unicode_characters

    \u0391  Α   Greek Capital Letter Alpha
    \u0392  Β   Greek Capital Letter Beta
    \u0393  Γ   Greek Capital Letter Gamma
    \u0394  Δ   Greek Capital Letter Delta
    \u0395  Ε   Greek Capital Letter Epsilon
    \u0396  Ζ   Greek Capital Letter Zeta
    \u0397  Η   Greek Capital Letter Eta
    \u0398  Θ   Greek Capital Letter Theta
    \u0399  Ι   Greek Capital Letter Iota
    \u039A  Κ   Greek Capital Letter Kappa
    \u039B  Λ   Greek Capital Letter Lambda
    \u039C  Μ   Greek Capital Letter Mu
    \u039D  Ν   Greek Capital Letter Nu
    \u039E  Ξ   Greek Capital Letter Xi
    \u039F  Ο   Greek Capital Letter Omicron
    \u03A0  Π   Greek Capital Letter Pi
    \u03A1  Ρ   Greek Capital Letter Rho
    \u03A3  Σ   Greek Capital Letter Sigma
    \u03A4  Τ   Greek Capital Letter Tau
    \u03A5  Υ   Greek Capital Letter Upsilon
    \u03A6  Φ   Greek Capital Letter Phi
    \u03A7  Χ   Greek Capital Letter Chi
    \u03A8  Ψ   Greek Capital Letter Psi
    \u03A9  Ω   Greek Capital Letter Omega
    \u03B1  α   Greek Small Letter alpha
    \u03B2  β   Greek Small Letter beta
    \u03B3  γ   Greek Small Letter gamma
    \u03B4  δ   Greek Small Letter delta
    \u03B5  ε   Greek Small Letter epsilon
    \u03B6  ζ   Greek Small Letter zeta
    \u03B7  η   Greek Small Letter eta
    \u03B8  θ   Greek Small Letter theta
    \u03B9  ι   Greek Small Letter iota
    \u03BA  κ   Greek Small Letter kappa
    \u03BB  λ   Greek Small Letter lambda
    \u03BC  μ   Greek Small Letter mu
    \u03BD  ν   Greek Small Letter nu
    \u03BE  ξ   Greek Small Letter xi
    \u03BF  ο   Greek Small Letter omicron
    \u03C0  π   Greek Small Letter pi
    \u03C1  ρ   Greek Small Letter rho
    \u03C2  ς   Greek Small Letter final sigma
    \u03C3  σ   Greek Small Letter sigma
    \u03C4  τ   Greek Small Letter tau
    \u03C5  υ   Greek Small Letter upsilon
    \u03C6  φ   Greek Small Letter phi
    \u03C7  χ   Greek Small Letter chi
    \u03C8  ψ   Greek Small Letter psi
    \u03C9  ω   Greek Small Letter omega
    

    有关使用unicode的字体的信息:https://en.wikipedia.org/wiki/List_of_typefaces#Unicode_fonts

    一些货币符号:

    # http://www.fileformat.info/info/unicode/category/Sc/list.htm
    Character   Name    Browser     Image
    \u0024  DOLLAR SIGN     $
    \u00A2  CENT SIGN   ¢
    \u00A3  POUND SIGN  £
    \u00A4  CURRENCY SIGN   ¤
    \u00A5  YEN SIGN    ¥
    \u058F  ARMENIAN DRAM SIGN
    \u060B  AFGHANI SIGN    ؋
    \u09F2  BENGALI RUPEE MARK  ৲
    \u09F3  BENGALI RUPEE SIGN  ৳
    \u09FB  BENGALI GANDA MARK
    \u0AF1  GUJARATI RUPEE SIGN     ૱
    \u0BF9  TAMIL RUPEE SIGN    ௹
    \u0E3F  THAI CURRENCY SYMBOL BAHT   ฿
    \u17DB  KHMER CURRENCY SYMBOL RIEL  ៛
    \u20A0  EURO-CURRENCY SIGN  ₠
    \u20A1  COLON SIGN  ₡
    \u20A2  CRUZEIRO SIGN   ₢
    \u20A3  FRENCH FRANC SIGN   ₣
    \u20A4  LIRA SIGN   ₤
    \u20A5  MILL SIGN   ₥
    \u20A6  NAIRA SIGN  ₦
    \u20A7  PESETA SIGN     ₧
    \u20A8  RUPEE SIGN  ₨
    \u20A9  WON SIGN    ₩
    \u20AA  NEW SHEQEL SIGN     ₪
    \u20AB  DONG SIGN   ₫
    \u20AC  EURO SIGN   €
    \u20AD  KIP SIGN    ₭
    \u20AE  TUGRIK SIGN     ₮
    \u20AF  DRACHMA SIGN    ₯
    \u20B0  GERMAN PENNY SIGN   ₰
    \u20B1  PESO SIGN   ₱
    \u20B2  GUARANI SIGN    ₲
    \u20B3  AUSTRAL SIGN    ₳
    \u20B4  HRYVNIA SIGN    ₴
    \u20B5  CEDI SIGN   ₵
    \u20B6  LIVRE TOURNOIS SIGN     ₶
    \u20B7  SPESMILO SIGN   ₷
    \u20B8  TENGE SIGN  ₸
    \u20B9  INDIAN RUPEE SIGN   ₹
    \u20BA  TURKISH LIRA SIGN   ₺
    \u20BB  NORDIC MARK SIGN    ₻
    \u20BC  MANAT SIGN  ₼
    \u20BD  RUBLE SIGN  ₽
    \uA838  NORTH INDIC RUPEE MARK
    \uFDFC  RIAL SIGN   ﷼
    \uFE69  SMALL DOLLAR SIGN   ﹩
    \uFF04  FULLWIDTH DOLLAR SIGN   $
    \uFFE0  FULLWIDTH CENT SIGN     ¢
    \uFFE1  FULLWIDTH POUND SIGN    £
    \uFFE5  FULLWIDTH YEN SIGN  ¥
    \uFFE6  FULLWIDTH WON SIGN
    

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