如何在R中对指数数取整？
指数数也称为科学数，这些数字以字母e表示。例如，数字12340000可以表示为1.234e+107。我们可以将其四舍五入为1.2e+107，而在R中，它可以借助singif函数完成。
例1
x1<−3.214735477e-05 signif(x1,digits=2) [1] 3.2e-05 signif(x1,digits=3) [1] 3.21e-05 signif(x1,digits=4) [1] 3.215e-05 signif(x1,digits=5) [1] 3.2147e-05
例2
x2<−c(3.735477e-05,2.14775e-06,3.247541e-11,2.2457441e-09) signif(x2,digits=2) [1] 3.7e-05 2.1e-06 3.2e-11 2.2e-09 signif(x2,digits=5) [1] 3.7355e-05 2.1478e-06 3.2475e-11 2.2457e-09 signif(x2,digits=4) [1] 3.735e-05 2.148e-06 3.248e-11 2.246e-09
范例3
x3<−sample(c(3.7357e−05,2.4145e−06,3.2441e−11,2.2457e−09),100,replace=TRUE) x3输出结果
[1] 2.4145e−06 3.7357e−05 2.4145e−06 3.2441e−11 2.2457e−09 2.2457e−09 [7] 3.7357e−05 2.4145e−06 3.2441e−11 2.4145e−06 2.4145e−06 3.2441e−11 [13] 3.2441e−11 2.4145e−06 3.7357e−05 2.4145e−06 2.2457e−09 2.4145e−06 [19] 2.4145e−06 2.2457e−09 2.2457e−09 2.2457e−09 2.2457e−09 2.4145e−06 [25] 3.2441e−11 3.2441e−11 2.4145e−06 3.2441e−11 3.7357e−05 3.7357e−05 [31] 2.2457e−09 2.2457e−09 3.2441e−11 3.2441e−11 2.4145e−06 2.4145e−06 [37] 2.2457e−09 3.2441e−11 3.7357e−05 2.2457e−09 2.4145e−06 3.2441e−11 [43] 3.2441e−11 3.2441e−11 3.7357e−05 2.4145e−06 3.2441e−11 2.2457e−09 [49] 2.2457e−09 3.2441e−11 3.7357e−05 2.4145e−06 3.7357e−05 3.2441e−11 [55] 2.4145e−06 3.2441e−11 2.4145e−06 2.2457e−09 2.2457e−09 2.2457e−09 [61] 2.4145e−06 3.2441e−11 2.4145e−06 2.4145e−06 2.4145e−06 3.2441e−11 [67] 2.2457e−09 2.4145e−06 3.2441e−11 2.2457e−09 2.2457e−09 3.7357e−05 [73] 2.2457e−09 2.4145e−06 3.7357e−05 2.4145e−06 3.2441e−11 3.7357e−05 [79] 2.4145e−06 3.2441e−11 3.2441e−11 3.7357e−05 3.7357e−05 2.4145e−06 [85] 3.7357e−05 2.2457e−09 3.7357e−05 3.7357e−05 3.2441e−11 2.2457e−09 [91] 3.2441e−11 3.7357e−05 3.2441e−11 3.7357e−05 3.2441e−11 2.4145e−06 [97] 2.2457e−09 2.2457e−09 2.4145e−06 3.2441e−11
示例
signif(x3,digits=2)输出结果
[1] 2.4e−06 3.7e−05 2.4e−06 3.2e−11 2.2e−09 2.2e−09 3.7e−05 2.4e−06 3.2e−11 [10] 2.4e−06 2.4e−06 3.2e−11 3.2e−11 2.4e−06 3.7e−05 2.4e−06 2.2e−09 2.4e−06 [19] 2.4e−06 2.2e−09 2.2e−09 2.2e−09 2.2e−09 2.4e−06 3.2e−11 3.2e−11 2.4e−06 [28] 3.2e−11 3.7e−05 3.7e−05 2.2e−09 2.2e−09 3.2e−11 3.2e−11 2.4e−06 2.4e−06 [37] 2.2e−09 3.2e−11 3.7e−05 2.2e−09 2.4e−06 3.2e−11 3.2e−11 3.2e−11 3.7e−05 [46] 2.4e−06 3.2e−11 2.2e−09 2.2e−09 3.2e−11 3.7e−05 2.4e−06 3.7e−05 3.2e−11 [55] 2.4e−06 3.2e−11 2.4e−06 2.2e−09 2.2e−09 2.2e−09 2.4e−06 3.2e−11 2.4e−06 [64] 2.4e−06 2.4e−06 3.2e−11 2.2e−09 2.4e−06 3.2e−11 2.2e−09 2.2e−09 3.7e−05 [73] 2.2e−09 2.4e−06 3.7e−05 2.4e−06 3.2e−11 3.7e−05 2.4e−06 3.2e−11 3.2e−11 [82] 3.7e−05 3.7e−05 2.4e−06 3.7e−05 2.2e−09 3.7e−05 3.7e−05 3.2e−11 2.2e−09 [91] 3.2e−11 3.7e−05 3.2e−11 3.7e−05 3.2e−11 2.4e−06 2.2e−09 2.2e−09 2.4e−06 [100] 3.2e−11
示例
signif(x3,digits=3)输出结果
[1] 2.41e−06 3.74e−05 2.41e−06 3.24e−11 2.25e−09 2.25e−09 3.74e−05 2.41e−06 [9] 3.24e−11 2.41e−06 2.41e−06 3.24e−11 3.24e−11 2.41e−06 3.74e−05 2.41e−06 [17] 2.25e−09 2.41e−06 2.41e−06 2.25e−09 2.25e−09 2.25e−09 2.25e−09 2.41e−06 [25] 3.24e−11 3.24e−11 2.41e−06 3.24e−11 3.74e−05 3.74e−05 2.25e−09 2.25e−09 [33] 3.24e−11 3.24e−11 2.41e−06 2.41e−06 2.25e−09 3.24e−11 3.74e−05 2.25e−09 [41] 2.41e−06 3.24e−11 3.24e−11 3.24e−11 3.74e−05 2.41e−06 3.24e−11 2.25e−09 [49] 2.25e−09 3.24e−11 3.74e−05 2.41e−06 3.74e−05 3.24e−11 2.41e−06 3.24e−11 [57] 2.41e−06 2.25e−09 2.25e−09 2.25e−09 2.41e−06 3.24e−11 2.41e−06 2.41e−06 [65] 2.41e−06 3.24e−11 2.25e−09 2.41e−06 3.24e−11 2.25e−09 2.25e−09 3.74e−05 [73] 2.25e−09 2.41e−06 3.74e−05 2.41e−06 3.24e−11 3.74e−05 2.41e−06 3.24e−11 [81] 3.24e−11 3.74e−05 3.74e−05 2.41e−06 3.74e−05 2.25e−09 3.74e−05 3.74e−05 [89] 3.24e−11 2.25e−09 3.24e−11 3.74e−05 3.24e−11 3.74e−05 3.24e−11 2.41e−06 [97] 2.25e−09 2.25e−09 2.41e−06 3.24e−11
例子4
x4<−sample(c(412.3657e−05,502.1445e−06,503.1441e−11,472.3257e−09),100,replace=TRUE) x4输出结果
[1] 4.123657e−03 4.723257e−07 4.723257e−07 5.031441e−09 5.021445e−04 [6] 5.031441e−09 4.723257e−07 4.723257e−07 4.123657e−03 5.021445e−04 [11] 5.031441e−09 4.123657e−03 5.021445e−04 4.723257e−07 5.021445e−04 [16] 5.021445e−04 4.123657e−03 4.723257e−07 5.031441e−09 4.723257e−07 [21] 5.031441e−09 5.031441e−09 5.021445e−04 4.723257e−07 5.031441e−09 [26] 5.021445e−04 5.021445e−04 5.021445e−04 4.723257e−07 4.723257e−07 [31] 4.723257e−07 5.031441e−09 5.031441e−09 5.031441e−09 4.723257e−07 [36] 4.123657e−03 5.031441e−09 5.021445e−04 4.723257e−07 4.723257e−07 [41] 5.021445e−04 5.031441e−09 4.723257e−07 4.123657e−03 5.021445e−04 [46] 5.021445e−04 5.031441e−09 4.723257e−07 5.031441e−09 5.031441e−09 [51] 4.723257e−07 4.723257e−07 4.123657e−03 4.723257e−07 5.021445e−04 [56] 4.123657e−03 4.723257e−07 5.021445e−04 5.031441e−09 4.723257e−07 [61] 5.021445e−04 4.123657e−03 4.723257e−07 4.123657e−03 5.021445e−04 [66] 4.723257e−07 5.031441e−09 5.031441e−09 4.723257e−07 4.123657e−03 [71] 4.123657e−03 5.031441e−09 5.031441e−09 4.123657e−03 4.723257e−07 [76] 5.031441e−09 5.031441e−09 5.031441e−09 4.723257e−07 5.021445e−04 [81] 5.021445e−04 5.021445e−04 4.723257e−07 4.123657e−03 5.021445e−04 [86] 5.031441e−09 4.123657e−03 4.723257e−07 5.021445e−04 4.723257e−07 [91] 4.723257e−07 4.123657e−03 5.031441e−09 4.723257e−07 5.031441e−09 [96] 5.021445e−04 5.021445e−04 4.123657e−03 5.021445e−04 5.031441e−09
示例
signif(x4,digits=2)输出结果
[1] 4.1e−03 4.7e−07 4.7e−07 5.0e−09 5.0e−04 5.0e−09 4.7e−07 4.7e−07 4.1e−03 [10] 5.0e−04 5.0e−09 4.1e−03 5.0e−04 4.7e−07 5.0e−04 5.0e−04 4.1e−03 4.7e−07 [19] 5.0e−09 4.7e−07 5.0e−09 5.0e−09 5.0e−04 4.7e−07 5.0e−09 5.0e−04 5.0e−04 [28] 5.0e−04 4.7e−07 4.7e−07 4.7e−07 5.0e−09 5.0e−09 5.0e−09 4.7e−07 4.1e−03 [37] 5.0e−09 5.0e−04 4.7e−07 4.7e−07 5.0e−04 5.0e−09 4.7e−07 4.1e−03 5.0e−04 [46] 5.0e−04 5.0e−09 4.7e−07 5.0e−09 5.0e−09 4.7e−07 4.7e−07 4.1e−03 4.7e−07 [55] 5.0e−04 4.1e−03 4.7e−07 5.0e−04 5.0e−09 4.7e−07 5.0e−04 4.1e−03 4.7e−07 [64] 4.1e−03 5.0e−04 4.7e−07 5.0e−09 5.0e−09 4.7e−07 4.1e−03 4.1e−03 5.0e−09 [73] 5.0e−09 4.1e−03 4.7e−07 5.0e−09 5.0e−09 5.0e−09 4.7e−07 5.0e−04 5.0e−04 [82] 5.0e−04 4.7e−07 4.1e−03 5.0e−04 5.0e−09 4.1e−03 4.7e−07 5.0e−04 4.7e−07 [91] 4.7e−07 4.1e−03 5.0e−09 4.7e−07 5.0e−09 5.0e−04 5.0e−04 4.1e−03 5.0e−04 [100] 5.0e−09
示例
signif(x4,digits=3)输出结果
[1] 4.12e−03 4.72e−07 4.72e−07 5.03e−09 5.02e−04 5.03e−09 4.72e−07 4.72e−07 [9] 4.12e−03 5.02e−04 5.03e−09 4.12e−03 5.02e−04 4.72e−07 5.02e−04 5.02e−04 [17] 4.12e−03 4.72e−07 5.03e−09 4.72e−07 5.03e−09 5.03e−09 5.02e−04 4.72e−07 [25] 5.03e−09 5.02e−04 5.02e−04 5.02e−04 4.72e−07 4.72e−07 4.72e−07 5.03e−09 [33] 5.03e−09 5.03e−09 4.72e−07 4.12e−03 5.03e−09 5.02e−04 4.72e−07 4.72e−07 [41] 5.02e−04 5.03e−09 4.72e−07 4.12e−03 5.02e−04 5.02e−04 5.03e−09 4.72e−07 [49] 5.03e−09 5.03e−09 4.72e−07 4.72e−07 4.12e−03 4.72e−07 5.02e−04 4.12e−03 [57] 4.72e−07 5.02e−04 5.03e−09 4.72e−07 5.02e−04 4.12e−03 4.72e−07 4.12e−03 [65] 5.02e−04 4.72e−07 5.03e−09 5.03e−09 4.72e−07 4.12e−03 4.12e−03 5.03e−09 [73] 5.03e−09 4.12e−03 4.72e−07 5.03e−09 5.03e−09 5.03e−09 4.72e−07 5.02e−04 [81] 5.02e−04 5.02e−04 4.72e−07 4.12e−03 5.02e−04 5.03e−09 4.12e−03 4.72e−07 [89] 5.02e−04 4.72e−07 4.72e−07 4.12e−03 5.03e−09 4.72e−07 5.03e−09 5.02e−04 [97] 5.02e−04 4.12e−03 5.02e−04 5.03e−09