R min and max function does not work for dates

I have a dataframe,df, with a date variable.

   locationID organe    

    <int>    <date>    

      1    1940-04-01

      2    1938-07-01

      3    1938-07-01

      4    1938-07-01

I want to compare the dates with a fixed time point,like "1938-12-1", to find the earliest date. I used the min function but failed.

df %>% mutate(earliest=min(organe,as.Date("1938-12-1")))





locationID organe     earliest  

<int>      <date>     <date>    

1       1940-04-01 1937-09-01

2       1938-07-01 1937-09-01

3       1938-07-01 1937-09-01

4       1938-07-01 1937-09-01

I don't know why min function does not work here, though it works well for the following situation

min(as.Date("1938-07-01"),as.Date("1938-12-1"))

[1] "1938-07-01"

Could anybody help?

asked Nov 12 '18 at 22:20

Li Feiyue

154

add a comment |

I have a dataframe,df, with a date variable.

   locationID organe    

    <int>    <date>    

      1    1940-04-01

      2    1938-07-01

      3    1938-07-01

      4    1938-07-01

I want to compare the dates with a fixed time point,like "1938-12-1", to find the earliest date. I used the min function but failed.

df %>% mutate(earliest=min(organe,as.Date("1938-12-1")))





locationID organe     earliest  

<int>      <date>     <date>    

1       1940-04-01 1937-09-01

2       1938-07-01 1937-09-01

3       1938-07-01 1937-09-01

4       1938-07-01 1937-09-01

I don't know why min function does not work here, though it works well for the following situation

min(as.Date("1938-07-01"),as.Date("1938-12-1"))

[1] "1938-07-01"

Could anybody help?

asked Nov 12 '18 at 22:20

Li Feiyue

154

add a comment |

I have a dataframe,df, with a date variable.

   locationID organe    

    <int>    <date>    

      1    1940-04-01

      2    1938-07-01

      3    1938-07-01

      4    1938-07-01

I want to compare the dates with a fixed time point,like "1938-12-1", to find the earliest date. I used the min function but failed.

df %>% mutate(earliest=min(organe,as.Date("1938-12-1")))





locationID organe     earliest  

<int>      <date>     <date>    

1       1940-04-01 1937-09-01

2       1938-07-01 1937-09-01

3       1938-07-01 1937-09-01

4       1938-07-01 1937-09-01

I don't know why min function does not work here, though it works well for the following situation

min(as.Date("1938-07-01"),as.Date("1938-12-1"))

[1] "1938-07-01"

Could anybody help?

asked Nov 12 '18 at 22:20

Li Feiyue

154

I have a dataframe,df, with a date variable.

   locationID organe    

    <int>    <date>    

      1    1940-04-01

      2    1938-07-01

      3    1938-07-01

      4    1938-07-01

I want to compare the dates with a fixed time point,like "1938-12-1", to find the earliest date. I used the min function but failed.

df %>% mutate(earliest=min(organe,as.Date("1938-12-1")))





locationID organe     earliest  

<int>      <date>     <date>    

1       1940-04-01 1937-09-01

2       1938-07-01 1937-09-01

3       1938-07-01 1937-09-01

4       1938-07-01 1937-09-01

I don't know why min function does not work here, though it works well for the following situation

min(as.Date("1938-07-01"),as.Date("1938-12-1"))

[1] "1938-07-01"

Could anybody help?

r date min

asked Nov 12 '18 at 22:20

Li Feiyue

154

asked Nov 12 '18 at 22:20

Li Feiyue

154

asked Nov 12 '18 at 22:20

Li Feiyue

154

asked Nov 12 '18 at 22:20

Li Feiyue

154

asked Nov 12 '18 at 22:20

Li Feiyue

154

add a comment |

1 Answer
1

active

oldest

votes

We can use pmin/pmax to get the minimum/maximum when one or both of the input argument is a vector of length greater than 1 (if both have length greater than 1, assumes the length to be same)

df %>% 

  mutate(earliest=pmin(organe,as.Date("1938-12-1")))

# A tibble: 4 x 3

#  locationID organe     earliest  

#      <int> <date>     <date>    

#1          1 1940-04-01 1938-12-01

#2          2 1938-07-01 1938-07-01

#3          3 1938-07-01 1938-07-01

#4          4 1938-07-01 1938-07-01

Or apply min after rowwise

df %>% 

   rowwise %>% 

   mutate(earliest=min(organe, as.Date("1938-12-1")))

Note that min returns a single value as output i.e.

min(5:1, 3)

#[1] 1



min(5:3, 1)

#[1] 1

For a vectorized minimum, use pmin. According to ?min

pmax*() and pmin*() take one or more vectors as arguments, recycle them to common length and return a single vector giving the ‘parallel’ maxima (or minima) of the argument vectors.

edited Nov 12 '18 at 22:35

answered Nov 12 '18 at 22:21

akrun

400k13189264

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

We can use pmin/pmax to get the minimum/maximum when one or both of the input argument is a vector of length greater than 1 (if both have length greater than 1, assumes the length to be same)

df %>% 

  mutate(earliest=pmin(organe,as.Date("1938-12-1")))

# A tibble: 4 x 3

#  locationID organe     earliest  

#      <int> <date>     <date>    

#1          1 1940-04-01 1938-12-01

#2          2 1938-07-01 1938-07-01

#3          3 1938-07-01 1938-07-01

#4          4 1938-07-01 1938-07-01

Or apply min after rowwise

df %>% 

   rowwise %>% 

   mutate(earliest=min(organe, as.Date("1938-12-1")))

Note that min returns a single value as output i.e.

min(5:1, 3)

#[1] 1



min(5:3, 1)

#[1] 1

For a vectorized minimum, use pmin. According to ?min

pmax*() and pmin*() take one or more vectors as arguments, recycle them to common length and return a single vector giving the ‘parallel’ maxima (or minima) of the argument vectors.

edited Nov 12 '18 at 22:35

answered Nov 12 '18 at 22:21

akrun

400k13189264

add a comment |

We can use pmin/pmax to get the minimum/maximum when one or both of the input argument is a vector of length greater than 1 (if both have length greater than 1, assumes the length to be same)

df %>% 

  mutate(earliest=pmin(organe,as.Date("1938-12-1")))

# A tibble: 4 x 3

#  locationID organe     earliest  

#      <int> <date>     <date>    

#1          1 1940-04-01 1938-12-01

#2          2 1938-07-01 1938-07-01

#3          3 1938-07-01 1938-07-01

#4          4 1938-07-01 1938-07-01

Or apply min after rowwise

df %>% 

   rowwise %>% 

   mutate(earliest=min(organe, as.Date("1938-12-1")))

Note that min returns a single value as output i.e.

min(5:1, 3)

#[1] 1



min(5:3, 1)

#[1] 1

For a vectorized minimum, use pmin. According to ?min

pmax*() and pmin*() take one or more vectors as arguments, recycle them to common length and return a single vector giving the ‘parallel’ maxima (or minima) of the argument vectors.

edited Nov 12 '18 at 22:35

answered Nov 12 '18 at 22:21

akrun

400k13189264

add a comment |

We can use pmin/pmax to get the minimum/maximum when one or both of the input argument is a vector of length greater than 1 (if both have length greater than 1, assumes the length to be same)

df %>% 

  mutate(earliest=pmin(organe,as.Date("1938-12-1")))

# A tibble: 4 x 3

#  locationID organe     earliest  

#      <int> <date>     <date>    

#1          1 1940-04-01 1938-12-01

#2          2 1938-07-01 1938-07-01

#3          3 1938-07-01 1938-07-01

#4          4 1938-07-01 1938-07-01

Or apply min after rowwise

df %>% 

   rowwise %>% 

   mutate(earliest=min(organe, as.Date("1938-12-1")))

Note that min returns a single value as output i.e.

min(5:1, 3)

#[1] 1



min(5:3, 1)

#[1] 1

For a vectorized minimum, use pmin. According to ?min

pmax*() and pmin*() take one or more vectors as arguments, recycle them to common length and return a single vector giving the ‘parallel’ maxima (or minima) of the argument vectors.

edited Nov 12 '18 at 22:35

answered Nov 12 '18 at 22:21

akrun

400k13189264

We can use pmin/pmax to get the minimum/maximum when one or both of the input argument is a vector of length greater than 1 (if both have length greater than 1, assumes the length to be same)

df %>% 

  mutate(earliest=pmin(organe,as.Date("1938-12-1")))

# A tibble: 4 x 3

#  locationID organe     earliest  

#      <int> <date>     <date>    

#1          1 1940-04-01 1938-12-01

#2          2 1938-07-01 1938-07-01

#3          3 1938-07-01 1938-07-01

#4          4 1938-07-01 1938-07-01

Or apply min after rowwise

df %>% 

   rowwise %>% 

   mutate(earliest=min(organe, as.Date("1938-12-1")))

Note that min returns a single value as output i.e.

min(5:1, 3)

#[1] 1



min(5:3, 1)

#[1] 1

For a vectorized minimum, use pmin. According to ?min

pmax*() and pmin*() take one or more vectors as arguments, recycle them to common length and return a single vector giving the ‘parallel’ maxima (or minima) of the argument vectors.

edited Nov 12 '18 at 22:35

answered Nov 12 '18 at 22:21

akrun

400k13189264

edited Nov 12 '18 at 22:35

answered Nov 12 '18 at 22:21

akrun

400k13189264

answered Nov 12 '18 at 22:21

akrun

400k13189264

answered Nov 12 '18 at 22:21

akrun

400k13189264

add a comment |

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