如何在 R 中创建复杂的字符串向量

Question

例如，我想创建一个这样的字符串向量

c('1987.6', '1987.7', '1987.8', '1987.9', '1987.10', '1987.11', '1987.12',
'1988.1', '1988.2', ..., '2020.12')

绝对不能一一写出来。

谢谢你的帮助！

Answer 1

使用 lapply 和 unlist 你可以这样做：

unlist(lapply(1987:1988, paste, 1:12, sep = "."))
#>  [1] "1987.1"  "1987.2"  "1987.3"  "1987.4"  "1987.5"  "1987.6"  "1987.7" 
#>  [8] "1987.8"  "1987.9"  "1987.10" "1987.11" "1987.12" "1988.1"  "1988.2" 
#> [15] "1988.3"  "1988.4"  "1988.5"  "1988.6"  "1988.7"  "1988.8"  "1988.9" 
#> [22] "1988.10" "1988.11" "1988.12"

Answer 2

另一种选择是

apply(expand.grid(1:12, 1987:2020), 1, (x) paste(rev(x), collapse = "."))
#>   [1] "1987.1"  "1987.2"  "1987.3"  "1987.4"  "1987.5"  "1987.6"  "1987.7" 
#>   [8] "1987.8"  "1987.9"  "1987.10" "1987.11" "1987.12" "1988.1"  "1988.2" 
#>  [15] "1988.3"  "1988.4"  "1988.5"  "1988.6"  "1988.7"  "1988.8"  "1988.9" 
#>  [22] "1988.10" "1988.11" "1988.12" "1989.1"  "1989.2"  "1989.3"  "1989.4" 
#>  [29] "1989.5"  "1989.6"  "1989.7"  "1989.8"  "1989.9"  "1989.10" "1989.11"
#>  [36] "1989.12" "1990.1"  "1990.2"  "1990.3"  "1990.4"  "1990.5"  "1990.6" 
#>  [43] "1990.7"  "1990.8"  "1990.9"  "1990.10" "1990.11" "1990.12" "1991.1" 
#>  [50] "1991.2"  "1991.3"  "1991.4"  "1991.5"  "1991.6"  "1991.7"  "1991.8" 
#>  [57] "1991.9"  "1991.10" "1991.11" "1991.12" "1992.1"  "1992.2"  "1992.3" 
#>  [64] "1992.4"  "1992.5"  "1992.6"  "1992.7"  "1992.8"  "1992.9"  "1992.10"
#>  [71] "1992.11" "1992.12" "1993.1"  "1993.2"  "1993.3"  "1993.4"  "1993.5" 
#>  [78] "1993.6"  "1993.7"  "1993.8"  "1993.9"  "1993.10" "1993.11" "1993.12"
#>  [85] "1994.1"  "1994.2"  "1994.3"  "1994.4"  "1994.5"  "1994.6"  "1994.7" 
#>  [92] "1994.8"  "1994.9"  "1994.10" "1994.11" "1994.12" "1995.1"  "1995.2" 
#>  [99] "1995.3"  "1995.4"  "1995.5"  "1995.6"  "1995.7"  "1995.8"  "1995.9" 
#> [106] "1995.10" "1995.11" "1995.12" "1996.1"  "1996.2"  "1996.3"  "1996.4" 
#> [113] "1996.5"  "1996.6"  "1996.7"  "1996.8"  "1996.9"  "1996.10" "1996.11"
#> [120] "1996.12" "1997.1"  "1997.2"  "1997.3"  "1997.4"  "1997.5"  "1997.6" 
#> [127] "1997.7"  "1997.8"  "1997.9"  "1997.10" "1997.11" "1997.12" "1998.1" 
#> [134] "1998.2"  "1998.3"  "1998.4"  "1998.5"  "1998.6"  "1998.7"  "1998.8" 
#> [141] "1998.9"  "1998.10" "1998.11" "1998.12" "1999.1"  "1999.2"  "1999.3" 
#> [148] "1999.4"  "1999.5"  "1999.6"  "1999.7"  "1999.8"  "1999.9"  "1999.10"
#> [155] "1999.11" "1999.12" "2000.1"  "2000.2"  "2000.3"  "2000.4"  "2000.5" 
#> [162] "2000.6"  "2000.7"  "2000.8"  "2000.9"  "2000.10" "2000.11" "2000.12"
#> [169] "2001.1"  "2001.2"  "2001.3"  "2001.4"  "2001.5"  "2001.6"  "2001.7" 
#> [176] "2001.8"  "2001.9"  "2001.10" "2001.11" "2001.12" "2002.1"  "2002.2" 
#> [183] "2002.3"  "2002.4"  "2002.5"  "2002.6"  "2002.7"  "2002.8"  "2002.9" 
#> [190] "2002.10" "2002.11" "2002.12" "2003.1"  "2003.2"  "2003.3"  "2003.4" 
#> [197] "2003.5"  "2003.6"  "2003.7"  "2003.8"  "2003.9"  "2003.10" "2003.11"
#> [204] "2003.12" "2004.1"  "2004.2"  "2004.3"  "2004.4"  "2004.5"  "2004.6" 
#> [211] "2004.7"  "2004.8"  "2004.9"  "2004.10" "2004.11" "2004.12" "2005.1" 
#> [218] "2005.2"  "2005.3"  "2005.4"  "2005.5"  "2005.6"  "2005.7"  "2005.8" 
#> [225] "2005.9"  "2005.10" "2005.11" "2005.12" "2006.1"  "2006.2"  "2006.3" 
#> [232] "2006.4"  "2006.5"  "2006.6"  "2006.7"  "2006.8"  "2006.9"  "2006.10"
#> [239] "2006.11" "2006.12" "2007.1"  "2007.2"  "2007.3"  "2007.4"  "2007.5" 
#> [246] "2007.6"  "2007.7"  "2007.8"  "2007.9"  "2007.10" "2007.11" "2007.12"
#> [253] "2008.1"  "2008.2"  "2008.3"  "2008.4"  "2008.5"  "2008.6"  "2008.7" 
#> [260] "2008.8"  "2008.9"  "2008.10" "2008.11" "2008.12" "2009.1"  "2009.2" 
#> [267] "2009.3"  "2009.4"  "2009.5"  "2009.6"  "2009.7"  "2009.8"  "2009.9" 
#> [274] "2009.10" "2009.11" "2009.12" "2010.1"  "2010.2"  "2010.3"  "2010.4" 
#> [281] "2010.5"  "2010.6"  "2010.7"  "2010.8"  "2010.9"  "2010.10" "2010.11"
#> [288] "2010.12" "2011.1"  "2011.2"  "2011.3"  "2011.4"  "2011.5"  "2011.6" 
#> [295] "2011.7"  "2011.8"  "2011.9"  "2011.10" "2011.11" "2011.12" "2012.1" 
#> [302] "2012.2"  "2012.3"  "2012.4"  "2012.5"  "2012.6"  "2012.7"  "2012.8" 
#> [309] "2012.9"  "2012.10" "2012.11" "2012.12" "2013.1"  "2013.2"  "2013.3" 
#> [316] "2013.4"  "2013.5"  "2013.6"  "2013.7"  "2013.8"  "2013.9"  "2013.10"
#> [323] "2013.11" "2013.12" "2014.1"  "2014.2"  "2014.3"  "2014.4"  "2014.5" 
#> [330] "2014.6"  "2014.7"  "2014.8"  "2014.9"  "2014.10" "2014.11" "2014.12"
#> [337] "2015.1"  "2015.2"  "2015.3"  "2015.4"  "2015.5"  "2015.6"  "2015.7" 
#> [344] "2015.8"  "2015.9"  "2015.10" "2015.11" "2015.12" "2016.1"  "2016.2" 
#> [351] "2016.3"  "2016.4"  "2016.5"  "2016.6"  "2016.7"  "2016.8"  "2016.9" 
#> [358] "2016.10" "2016.11" "2016.12" "2017.1"  "2017.2"  "2017.3"  "2017.4" 
#> [365] "2017.5"  "2017.6"  "2017.7"  "2017.8"  "2017.9"  "2017.10" "2017.11"
#> [372] "2017.12" "2018.1"  "2018.2"  "2018.3"  "2018.4"  "2018.5"  "2018.6" 
#> [379] "2018.7"  "2018.8"  "2018.9"  "2018.10" "2018.11" "2018.12" "2019.1" 
#> [386] "2019.2"  "2019.3"  "2019.4"  "2019.5"  "2019.6"  "2019.7"  "2019.8" 
#> [393] "2019.9"  "2019.10" "2019.11" "2019.12" "2020.1"  "2020.2"  "2020.3" 
#> [400] "2020.4"  "2020.5"  "2020.6"  "2020.7"  "2020.8"  "2020.9"  "2020.10"
#> [407] "2020.11" "2020.12"

^{创建于 2022-12-17 reprex v2.0.2}